[seqfan] Re: More stupid thingies with commas, sums & primes
Christopher Hunt gribble
cgribble263 at btinternet.com
Wed Oct 19 23:44:51 CEST 2011
My C++ program halts with a stack overflow exception for n = 100000.
However, for n = 10000 and 20000 the prime sum frequencies are:
2 773 2762
3 483 1315
5 1219 3051
7 1835 3835
11 3720 6732
13 1197 1362
17 772 942
The frequencies with which the partitions of the prime sums into the least
significant digit (LSD) of a(n-1) and the most significant digit (MSD) of
a(n) are for n = 10000:
MSD 0 1 2 3 4 5 6 7
8 9
LSD
0 0 0 273 219 0 225 0 284 0
0
1 0 500 1 0 198 0 303 0 0
0
2 0 263 0 209 0 227 0 0 0
302
3 0 0 323 0 207 0 0 0 471
0
4 0 264 0 209 0 0 0 511 0
17
5 0 0 325 0 0 0 507 0 168
0
6 0 280 0 0 0 436 0 284 0
0
7 0 0 0 0 698 0 301 0
0 0
8 0 0 0 474 0 223 0 0
0 300
9 0 0 321 0 204 0 0 0 472
0
and for n = 20000:
MSD 0 1 2 3 4 5 6 7
8 9
LSD
0 0 0 1262 219 0 225 0 295 0
0
1 0 1500 1 0 198 0 303 0 0
0
2 0 1095 0 209 0 227 0 0 0
469
3 0 0 1322 0 207 0 0 0 471
0
4 0 1097 0 209 0 0 0 522 0
172
5 0 0 1325 0 0 0 507 0 168
0
6 0 1269 0 0 0 436 0 294 0
0
7 0 0 0 0 1698 0 301 0
0 0
8 0 0 0 1306 0 223 0 0
0 470
9 0 0 1323 0 204 0 0 0 472
0
It is interesting to note that some frequencies have not changed.
For n = 10000:
The smallest integer not present in the first 10000 terms = 7968
The largest integer present in the first 10000 terms = 40195
For n = 20000:
The smallest integer not present in the first 20000 terms = 13851
The largest integer present in the first 20000 terms = 41195
Chris
-----Original Message-----
From: seqfan-bounces at list.seqfan.eu [mailto:seqfan-bounces at list.seqfan.eu]
On Behalf Of Ed Jeffery
Sent: 19 October 2011 4:46 PM
To: seqfan at list.seqfan.eu
Subject: [seqfan] Re: More stupid thingies with commas, sums & primes
Then what about the graph of Chris' results for the distribution as n
becomes large: does it increase and peak at the prime 7 (the midpoint
between the primes 2 and 17) and is it symmetrical about the prime 7? -- Ed
Jeffery
>The frequencies of occurrence of the 7 prime sums over the first 10000
terms
>are:
>2 1788448
>3 2318299
>5 3624036
>7 4340644
>11 4100476
>13 2246844
>17 503513
>suggesting non-uniformity of distribution.
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