A353925 Product_{n>=1} (1 + a(n)*x^n) = 1 + Sum_{n>=1} phi(n)*x^n, where phi = A000010.

1, 1, 1, 1, 2, -2, 4, -3, 4, -6, 14, -18, 30, -32, 48, -73, 128, -182, 286, -394, 578, -804, 1386, -1936, 3172, -4298, 7102, -10202, 16414, -23798, 38056, -54997, 86658, -125180, 203396, -292650, 475536, -685314, 1100728, -1619952, 2601166, -3808952, 6114666, -9045400, 14352568

Offset

1,5

Links

Table of n, a(n) for n=1..45.

Mathematica

A[m_, n_] := A[m, n] = Which[m == 1, EulerPhi[n], m > n >= 1, 0, True, A[m - 1, n] - A[m - 1, m - 1] A[m, n - m + 1]]; a[n_] := A[n, n]; a /@ Range[1, 45]

Crossrefs

Cf. A000010, A320778, A328774, A353923, A353924, A353926.

Sequence in context: A205793 A178431 A233574 * A157927 A374396 A227256

Adjacent sequences: A353922 A353923 A353924 * A353926 A353927 A353928

Keyword

sign

Author

Ilya Gutkovskiy, May 11 2022

Status

approved