A304335 Sum of digits of (2*n-1)!!.

1, 1, 3, 6, 6, 18, 18, 18, 18, 36, 45, 45, 36, 63, 72, 72, 90, 90, 108, 108, 126, 108, 144, 144, 135, 144, 153, 180, 180, 171, 180, 198, 198, 189, 216, 243, 243, 234, 252, 225, 243, 261, 252, 297, 306, 333, 360, 324, 342, 342, 315, 360, 369, 378, 396, 387, 387, 414

Offset

0,3

Links

Seiichi Manyama, Table of n, a(n) for n = 0..1000

Formula

a(n) = A007953(A001147(n)).

Maple

a:= n-> add(i, i=convert(doublefactorial(2*n-1), base, 10)):
seq(a(n), n=0..60);  # Alois P. Heinz, May 11 2018

Prog

(PARI) {a(n) = sumdigits((2*n)!/(n!*2^n))}

Crossrefs

Cf. A001147, A004152.

Sequence in context: A103463 A370154 A265026 * A223048 A319446 A181372

Adjacent sequences: A304332 A304333 A304334 * A304336 A304337 A304338

Keyword

nonn,base

Author

Seiichi Manyama, May 11 2018

Status

approved