A216703 a(n) = Product_{k=1..n} (49 - 7/k).

1, 42, 1911, 89180, 4213755, 200574738, 9594158301, 460519598448, 22162505675310, 1068725273676060, 51619430718553698, 2496503376570051576, 120872371815599997138, 5857661095679076784380, 284096563140435224042430, 13788153197749122873525936

Offset

0,2

Comments

This sequence is generalizable: Product_{k=1..n} (q^2 - q/k) = (q^n/n!) * Product_{k=0..n-1} (q*k + q-1) = expansion of (1- x*q^2)^((1-q)/q).

Links

Table of n, a(n) for n=0..15.

Maple

seq(product(49-7/k, k=1.. n), n=0..20);
seq((7^n/n!)*product(7*k+6, k=0.. n-1), n=0..20);

Crossrefs

Cf. A004988, A049382, A004994, A216702.

Sequence in context: A009986 A041841 A236270 * A258393 A187365 A294978

Adjacent sequences: A216700 A216701 A216702 * A216704 A216705 A216706

Keyword

nonn

Author

Michel Lagneau, Sep 16 2012

Status

approved