A323340 Denominator of the sum of inverse products of parts in all compositions of n.

1, 1, 2, 3, 3, 60, 360, 70, 1680, 3780, 75600, 138600, 285120, 129729600, 363242880, 3405402000, 1009008000, 308756448000, 5557616064000, 52797352608000, 351982350720000, 221748880953600, 1524523556556000, 738190353700800, 13464592051502592000

Offset

0,3

Comments

Denominators of the INVERT transform of reciprocal integers.

Links

Alois P. Heinz, Table of n, a(n) for n = 0..506

Formula

a(n) = denominator( A007840(n)/n! ).

Maple

b:= proc(n) option remember;
     `if`(n=0, 1, add(b(n-j)/j, j=1..n))
    end:
a:= n-> denom(b(n)):
seq(a(n), n=0..25);

Mathematica

nmax = 20; Denominator[CoefficientList[Series[1/(1 + Log[1-x]), {x, 0, nmax}], x]] (* Vaclav Kotesovec, Feb 12 2024 *)

Crossrefs

See A323339 for more information.

Cf. A000142, A007840.

Sequence in context: A242786 A214219 A365223 * A280895 A088266 A116889

Adjacent sequences: A323337 A323338 A323339 * A323341 A323342 A323343

Keyword

nonn,frac

Author

Alois P. Heinz, Jan 11 2019

Status

approved