A337990 Number of compositions (ordered partitions) of n^n into powers of n.

1, 1, 6, 26426, 773527571233557154337704151068262296

Offset

0,3

Comments

The next term is too large to include.

Links

Table of n, a(n) for n=0..4.

Index entries for sequences related to compositions

Formula

a(n) = [x^(n^n)] 1 / (1 - Sum_{k>=0} x^(n^k)), for n > 1.

Example

a(2) = 6 because 2^2 = 4 and we have [4], [2, 2], [2, 1, 1] (3 permutations), [1, 1, 1, 1] and 1 + 1 + 3 + 1 = 6.

Mathematica

Join[{1, 1}, Table[SeriesCoefficient[1/(1 - Sum[x^(n^k), {k, 0, n}]), {x, 0, n^n}], {n, 2, 4}]]

Crossrefs

Cf. A145514, A248377.

Sequence in context: A283887 A241650 A368064 * A143780 A225716 A159429

Adjacent sequences: A337987 A337988 A337989 * A337991 A337992 A337993

Keyword

nonn

Author

Ilya Gutkovskiy, Oct 06 2020

Status

approved