A174462 a(n) = Sum_{d|n} binomial(n,d)^2.

1, 5, 10, 53, 26, 662, 50, 5749, 7138, 65630, 122, 1151702, 170, 11787102, 9225260, 168963957, 290, 2709216086, 362, 34398664078, 13522807742, 497634360470, 530, 7871610432598, 2822797526, 108172480466302, 21966337136980

Offset

1,2

Comments

Analog to the central binomial coefficients: A000984(n) = Sum_{k=0..n} C(n,k)^2.

Links

Seiichi Manyama, Table of n, a(n) for n = 1..1667

Formula

Logarithmic derivative of A174461.

Prog

(PARI) {a(n)=sumdiv(n, d, binomial(n, d)^2)}

Crossrefs

Cf. A056045, A174461.

Sequence in context: A205884 A032088 A081076 * A277247 A270131 A271295

Adjacent sequences: A174459 A174460 A174461 * A174463 A174464 A174465

Keyword

nonn

Author

Paul D. Hanna, Apr 04 2010

Status

approved