A072953 a(n)=sum(k=1,n,C(n,n reduced (mod k))).

1, 2, 5, 7, 22, 25, 79, 124, 276, 444, 1267, 1657, 4435, 7753, 17327, 28309, 72728, 110949, 279663, 476090, 1071672, 1834419, 4512625, 7194685, 17326148, 30229021, 68385742, 117709413, 280395840, 466385404, 1099376097, 1923155966

Offset

1,2

Links

Table of n, a(n) for n=1..32.

Formula

Observation: lim n -> infinity a(n+2)/a(n) = 4 and it seems that a(n+2)/a(n) < 4 or >4 for infinitely many values of n.

Mathematica

Table[Sum[Binomial[n, Mod[n, k]], {k, n}], {n, 40}] (* Harvey P. Dale, Jul 16 2017 *)

Prog

(PARI) a(n)=sum(k=1, n, binomial(n, n%k))

Crossrefs

Sequence in context: A327322 A160820 A158357 * A243394 A175552 A279756

Adjacent sequences: A072950 A072951 A072952 * A072954 A072955 A072956

Keyword

nonn

Author

Benoit Cloitre, Aug 20 2002

Status

approved