A344580 Numbers k such that A101203(k) is prime.

4, 5, 6, 7, 8, 15, 18, 19, 26, 33, 44, 50, 64, 69, 74, 115, 138, 139, 150, 151, 161, 170, 208, 213, 218, 232, 233, 237, 246, 258, 275, 289, 290, 303, 309, 310, 311, 333, 334, 340, 352, 353, 360, 369, 376, 405, 412, 441, 483, 489, 495, 502, 503, 507, 514, 529, 610, 615, 633, 638, 645, 648, 658

Offset: 1

Author

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

Keywords

• nonn

Comments

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.

Examples

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

Links

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

Crossrefs

Cf. A101203, A228102.

Programs

Maple

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]);