# [seqfan] Re: A172043 and many more

Joerg Arndt arndt at jjj.de
Wed Mar 3 16:47:22 CET 2010

```* Joerg Arndt <arndt at jjj.de> [Mar 03. 2010 15:27]:
> Dear Vincenzo,
> please edit (or remove) the sequence A172043.
>
> [...]

Done editing (but on oeisf site, let's see whether
this goes thru).

Btw. the preview does nothing on the oeisf edit-page.

context diff:

*** /home/oeis/wwwfiles/sequences/tmp/tempC1.9808	Wed Mar  3 10:46:51 2010
--- /home/oeis/wwwfiles/sequences/tmp/tempC2.9808	Wed Mar  3 10:46:51 2010
***************
*** 2,10 ****
%S A172043 1,5,19,43,77,121,175,239,313,397,491,595,709,833,967,1111,1265,1429,
%T A172043 1603,1787,1981,2185,2399,2623,2857,3101,3355,3619,3893,4177,4471,4775,
%U A172043 5089,5413,5747,6091,6445,6809,7183,7567,7961,8365,8779,9203,9637,10081
! %N A172043 Numbers n such that n^2+1=0(mod.p), (with p=2 or p=4k+1)
! %F A172043 a(n)=5*n^2-n+1
! %e A172043 For n=0, a(0)=1; n=1, a(1)=5; n=2, a(2)=19, n=3, a(3)=43
! %K A172043 nonn
%O A172043 0,2
%A A172043 Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jan 29 2010
--- 2,9 ----
%S A172043 1,5,19,43,77,121,175,239,313,397,491,595,709,833,967,1111,1265,1429,
%T A172043 1603,1787,1981,2185,2399,2623,2857,3101,3355,3619,3893,4177,4471,4775,
%U A172043 5089,5413,5747,6091,6445,6809,7183,7567,7961,8365,8779,9203,9637,10081
! %N A172043 a(n)=5*n^2-n+1
! %K A172043 nonn, dumb
%O A172043 0,2
+ %o A048272 (PARI) for(n=0,100,print1(5*n^2-n+1,", "))
%A A172043 Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jan 29 2010

New entry alone:
%I A172043
%S A172043 1,5,19,43,77,121,175,239,313,397,491,595,709,833,967,1111,1265,1429,
%T A172043 1603,1787,1981,2185,2399,2623,2857,3101,3355,3619,3893,4177,4471,4775,
%U A172043 5089,5413,5747,6091,6445,6809,7183,7567,7961,8365,8779,9203,9637,10081
%N A172043 a(n)=5*n^2-n+1
%K A172043 nonn, dumb
%O A172043 0,2
%o A048272 (PARI) for(n=0,100,print1(5*n^2-n+1,", "))
%A A172043 Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jan 29 2010

```

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