login
Number of partitions of n that contain at least one odd prime as a part.
1

%I #24 Oct 12 2022 17:16:06

%S 0,0,0,1,1,3,4,8,10,17,22,35,45,67,86,123,156,216,273,369,463,613,765,

%T 997,1236,1587,1958,2485,3049,3830,4677,5823,7077,8740,10576,12971,

%U 15629,19046,22862,27701,33125,39928,47579,57078,67788,80963,95852,114023

%N Number of partitions of n that contain at least one odd prime as a part.

%F a(n) = A000041(n) - A355195(n).

%e For n = 6 the partitions of 6 that contain at least one odd prime as a part are [3, 3], [5, 1], [3, 2, 1], [3, 1, 1, 1]. There are four of these partitions so a(6) = 4.

%o (PARI) a(n) = my(nb=0); forpart(p=n, if (#select(x->((x>2) && isprime(x)), Vec(p)) >=1, nb++);); nb; \\ _Michel Marcus_, Jun 23 2022

%Y Cf. A000041, A065091, A235945, A353188, A355195.

%K nonn

%O 0,6

%A _Omar E. Pol_, Jun 23 2022

%E More terms from _Michel Marcus_, Jun 23 2022