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 A344580 #7 May 25 2021 01:38:07 %S A344580 4,5,6,7,8,15,18,19,26,33,44,50,64,69,74,115,138,139,150,151,161,170, %T A344580 208,213,218,232,233,237,246,258,275,289,290,303,309,310,311,333,334, %U A344580 340,352,353,360,369,376,405,412,441,483,489,495,502,503,507,514,529,610,615,633,638,645,648,658 %N A344580 Numbers k such that A101203(k) is prime. %C A344580 Numbers k such that the sum of nonprimes <= k is prime. %C A344580 If p is prime then p is a member if and only if p-1 is a member. %H A344580 Robert Israel, <a href="/A344580/b344580.txt">Table of n, a(n) for n = 1..10000</a> %e A344580 a(3) = 6 is a member because A101203(6) = 1+4+6 = 11 is prime. %p A344580 s:= proc(n) option remember; if isprime(n) then procname(n-1) else procname(n-1)+ n fi end proc: %p A344580 s(1):= 1: %p A344580 select(n -> isprime(s(n)), [$1..1000]); %Y A344580 Cf. A101203, A228102. %K A344580 nonn %O A344580 1,1 %A A344580 _J. M. Bergot_ and _Robert Israel_, May 23 2021