A243935 Numbers m such that 5 divides A000041(m).

4, 7, 9, 14, 18, 19, 23, 24, 27, 29, 34, 38, 39, 44, 49, 54, 58, 59, 61, 64, 66, 68, 69, 71, 74, 79, 82, 84, 89, 94, 97, 99, 103, 104, 109, 114, 119, 120, 124, 127, 128, 129, 130, 134, 136, 139, 140, 142, 144, 149, 154, 159, 163, 164, 165, 169, 170, 173, 174

Offset

1,1

Links

Bruno Berselli, Table of n, a(n) for n = 1..1000

Mathematica

Select[Range[200], Mod[PartitionsP[#], 5] == 0 &]

Prog

(Sage)
# From Peter Luschny in A000041
@CachedFunction
def A000041(n):
    if n == 0: return 1
    S = 0; J = n-1; k = 2
    while 0 <= J:
        T = A000041(J)
        S = S+T if is_odd(k//2) else S-T
        J -= k if is_odd(k) else k//2
        k += 1
    return S
[n for n in (0..200) if mod(A000041(n), 5) == 0]
(Magma) [n: n in [1..200] | IsZero(NumberOfPartitions(n) mod 5)];
(PARI) is(n)=numbpart(n)%5==0 \\ Charles R Greathouse IV, Apr 08 2015

Crossrefs

Numbers m such that k divides A000041(m), where k is prime: A001560 (k=2), A083214 (k=3), this sequence (k=5), A243936 (k=7), A027827 (k=11), A071750 (k=13). For k composite: A237278 (k=4), A035700 (k=12).

Sequence in context: A310965 A035510 A187898 * A310966 A287559 A032778

Adjacent sequences: A243932 A243933 A243934 * A243936 A243937 A243938

Keyword

nonn,easy

Author

Bruno Berselli, Jun 15 2014

Status

approved