This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A234847 #7 Aug 12 2014 08:36:12 %S A234847 997,1049,1709,2137,2953,3889,3989,28643,43451,121937,189239,225077, %T A234847 662843,785303,860143,874351,959209,1026229,1051151,1271687,1285507, %U A234847 1772297,2525801,2834413,2865199,3456053,3484361,3538477,4402241,4762267,8240539,11557543,15774301 %N A234847 Primes which are sum of the first k composite numbers and such that the sum of the first k+1 composites is also prime. %H A234847 Harvey P. Dale, <a href="/A234847/b234847.txt">Table of n, a(n) for n = 1..1000</a> %e A234847 a(1)= 997 is prime and sum of the first 35 composites from 4 to 51. And the sum of the first 36 composites is 1049 and is also prime. %t A234847 Transpose[Select[Partition[Accumulate[Select[Range[ 10000], CompositeQ]],2,1],AllTrue[ #,PrimeQ]&]][[1]] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Aug 12 2014 *) %o A234847 (PARI) i=0; b=0; for( a=2, 6000, if( !isprime(a) ,i=i+1; b=b+a; if(( isprime(b) & isprime(b+a+1)& !isprime(a+1)) || (isprime(b) & isprime(b+a+2) & isprime(a+1)), print1(b,", ")))) %Y A234847 Cf. A053782 %K A234847 nonn %O A234847 1,1 %A A234847 _Robin Garcia_, Dec 31 2013