A038045 - OEIS

A038045

Shifts left under transform T where Ta is phi DCONV a.

1, 1, 2, 4, 7, 11, 17, 23, 33, 43, 58, 68, 97, 109, 138, 168, 211, 227, 298, 316, 401, 459, 537, 559, 723, 771, 892, 988, 1173, 1201, 1507, 1537, 1791, 1947, 2190, 2324, 2825, 2861, 3195, 3437, 3999, 4039, 4794, 4836, 5481, 5971, 6552, 6598, 7775

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OFFSET

1,3

COMMENTS

Eigensequence of triangle A054523; i.e., multiplication by A054523 shifts the sequence to (1, 2, 4, ...). - Gary W. Adamson, Apr 26 2009

LINKS

Table of n, a(n) for n=1..49.

FORMULA

a(1) = 1; a(n+1) = Sum_{d|n} phi(n/d) * a(d). - Ilya Gutkovskiy, Feb 23 2020

MATHEMATICA

a[1] = 1; a[n_] := a[n] = Sum[EulerPhi[(n-1)/d]*a[d], {d, Divisors[n-1]}]; Table[a[n], {n, 1, 100}] (* Vaclav Kotesovec, Feb 23 2020 *)

CROSSREFS

Cf. A000010, A054523.

Sequence in context: A101978 A076273 A024455 * A178063 A095233 A062434

Adjacent sequences: A038042 A038043 A038044 * A038046 A038047 A038048

KEYWORD

nonn,eigen

AUTHOR

Christian G. Bower

STATUS

approved