<div> <br>Hello: <br>You wrote: <br>"Also, I was surprised to find that this seq wasn't already in the OEIS: <br> n such that 10^n + prime(n) is prime..." <br> <br>The sequence A125148, of which I am the author, was modified by Klaus Brockhaus so that it could remain in OEIS, but originally that sequence was the following one:
<br> <br>Prime Numbers that p = (10^x*z)+Y where Y it is an odd number prime or composite not divisible for 5 and x is equal or bigger that the quantity of ciphers of Y. <br> </div>
<div>Originally I deduced it for the odd composites , in way of demonstrating that for any combination of ciphers that they finish in 1,3,7, or 9 it is possible to find a prime number adding a power of 10 equal or bigger than the ciphers cuantity of Y multiplied for a number bigger than 0.
<br>Example: <br>9 are the first odd composite number but 10^1*1+9=19 <br>21 are the second odd composite number (not divisible for 5) but 10^2*4+21=421 <br>27 are the third add composite (not divisible for 5) but 10^2*1+27=127.
<br>etc.. <br>In: <br><a href="http://primes.utm.edu/curios/page.php?number_id=6894&submitter=Xordan">http://primes.utm.edu/curios/page.php?number_id=6894&submitter=Xordan</a> <br><a href="http://primes.utm.edu/curios/page.php?number_id=6983&submitter=Xordan">
http://primes.utm.edu/curios/page.php?number_id=6983&submitter=Xordan</a> <br>you find the numbers: <br>28123456789 <br>The first prime number ending with all the ciphers (1 to 9) in order, and: <br>212345678987654321
<br>The first prime number ending with all the ciphers (1 to 9 to 1) in palindromic order. <br> <br> These numbers were obtained form that algorithm, besides other curiosities that I have not remitted like: <br>11987654321234567879
<br>The first prime number ending with all the ciphers (9 to 1 to 9) in palindromic order. <br>Hope you find some resemblance...</div>
<div>Greetings</div>
<div> </div>
<div>XORDAN<br>Original in spanish, translated bysoftware</div>
<div><span class="gmail_quote">.2007/6/3, Jason Earls <<a href="mailto:jcearls@cableone.net">jcearls@cableone.net</a>>:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Dear Seqfans,<br><br>I recently found these twin probable primes:<br><br>2357*2^7532+105525<br>2357*2^7532+105527
<br>(2271 digits)<br><br>Anyone know of databases that keep track of these? They shouldn't be in the<br>OEIS, should they?<br><br>Also, I was surprised to find that this seq wasn't already in the OEIS:<br><br>n such that 10^n + prime(n) is prime.
<br>2,4,27,63,756,899,<br><br>I used PFGW to check up to 8000 and didn't find anymore.<br><br>Worth submitting?<br><br>Regards,<br>Jason<br>======<br>Check out my novel, Red Zen:<br><a href="http://tinyurl.com/2ylpml">
http://tinyurl.com/2ylpml</a><br><br><br><br></blockquote></div><br><br clear="all"><br>-- <br><a href="mailto:xordan@hotmail.com">xordan@hotmail.com</a><br><a href="mailto:xordan_co@yahoo.com">xordan_co@yahoo.com</a><br>
<a href="mailto:xordan.tom@gmail.com">xordan.tom@gmail.com</a>