1,1

Numbers k such that the sum of nonprimes <= k is prime.

If p is prime then p is a member if and only if p-1 is a member.

Robert Israel, Table of n, a(n) for n = 1..10000

a(3) = 6 is a member because A101203(6) = 1+4+6 = 11 is prime.

s:= proc(n) option remember; if isprime(n) then procname(n-1) else procname(n-1)+ n fi end proc:

s(1):= 1:

select(n -> isprime(s(n)), [$1..1000]);

Cf. A101203, A228102.

Sequence in context: A050038 A285218 A059709 * A071623 A274552 A280682

Adjacent sequences: A344577 A344578 A344579 * A344581 A344582 A344583

nonn

J. M. Bergot and Robert Israel, May 23 2021

approved