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A347428 Expansion of g.f. Product_{k>=2} 1/(1-x^phi(k)). 0
1, 1, 4, 4, 14, 14, 40, 40, 106, 106, 254, 254, 582, 582, 1256, 1256, 2619, 2619, 5251, 5251, 10247, 10247, 19424, 19424, 36037, 36037, 65364, 65364, 116455, 116455, 203743, 203743, 351095, 351095, 595921, 595921, 998386, 998386, 1651231, 1651231, 2700099, 2700099 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..41.

David P. Roberts and Fernando Rodriguez Villegas, Hypergeometric Motives, arXiv:2109.00027 [math.AG], 2021. See (5.2) p. 6.

FORMULA

From Vaclav Kotesovec, Sep 02 2021: (Start)

For n>0, a(n) = A120963(n) - A120963(n-1).

log(a(n)) ~ sqrt(105*zeta(3)*n)/Pi. (End)

PROG

(PARI) my(x='x+O('x^45)); Vec(prod(k=2, 50, 1/(1-x^eulerphi(k))))

CROSSREFS

Cf. A000010 (phi), A014197, A051894, A120963 (similar g.f.).

Sequence in context: A097335 A255297 A339319 * A263870 A263796 A263871

Adjacent sequences:  A347425 A347426 A347427 * A347429 A347430 A347431

KEYWORD

nonn

AUTHOR

Michel Marcus, Sep 02 2021

STATUS

approved

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Last modified December 6 15:23 EST 2021. Contains 349563 sequences. (Running on oeis4.)