A345179 a(1) = 1; a(n) = Sum_{d|n, d < n} binomial(n/d,d) * a(d).

1, 2, 3, 6, 5, 12, 7, 20, 12, 30, 11, 54, 13, 56, 45, 78, 17, 150, 19, 140, 126, 132, 23, 414, 30, 182, 279, 420, 29, 630, 31, 692, 528, 306, 140, 1770, 37, 380, 897, 1960, 41, 1638, 43, 2486, 2040, 552, 47, 5586, 56, 1910, 2091, 4992, 53, 4212, 2365, 6874, 2964, 870, 59, 19020

Offset

1,2

Links

Table of n, a(n) for n=1..60.

Mathematica

a[1] = 1; a[n_] := a[n] = Sum[If[d < n, Binomial[n/d, d] a[d], 0], {d, Divisors[n]}]; Table[a[n], {n, 1, 60}]

Crossrefs

Cf. A008578 (fixed points), A074206, A318636, A330017, A345136.

Sequence in context: A001634 A172989 A095113 * A367584 A002517 A253568

Adjacent sequences: A345176 A345177 A345178 * A345180 A345181 A345182

Keyword

nonn

Author

Ilya Gutkovskiy, Jun 10 2021

Status

approved