A274489 a(n) = floor(sinh(n) / n^2).

1, 0, 1, 1, 2, 5, 11, 23, 50, 110, 247, 565, 1308, 3067, 7264, 17355, 41790, 101327, 247205, 606456, 1495255, 3703422, 9210589, 22994029, 57603919, 144770421, 364916488, 922357821, 2337297441

Offset

1,5

Comments

This sequence has some elements in common with A018112 (-> elements 1, 2, 5, 11, 23, 50, 110).

The sum of the reciprocals of a(n) (for n>=2) converges to 2.870623225848376377857...

Links

Table of n, a(n) for n=1..29.

Formula

a(n) = floor(sinh(n)/(n^2)), for n >= 1.

Mathematica

Table[Floor[Sinh[n]/n^2], {n, 30}] (* Harvey P. Dale, Nov 15 2018 *)

Prog

(PARI) a(n)=localprec(19); localprec((n-log(2))\log(10)+9); sinh(n)\n^2 \\ Charles R Greathouse IV, Nov 10 2016

Crossrefs

Sequence in context: A358912 A083380 A018112 * A192415 A201779 A067149

Adjacent sequences: A274486 A274487 A274488 * A274490 A274491 A274492

Keyword

nonn,easy,hear

Author

Alessandro Polcini, Nov 10 2016

Status

approved