login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A291489 Expansion of the series reversion of -1 + Product_{k>=1} (1 + x^k)^k. 2
1, -2, 3, 2, -41, 196, -541, 229, 7235, -48228, 175956, -254933, -1575661, 14909191, -67194669, 153944915, 292516673, -4968647665, 27275432639, -82747735226, 3883854725, 1660136515050, -11302429310683, 42362000190568, -53376259124482, -520085199830413, 4671353423344131 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Reversion of g.f. (with constant term omitted) for A026007.

LINKS

Table of n, a(n) for n=1..27.

N. J. A. Sloane, Transforms

Eric Weisstein's World of Mathematics, Series Reversion

Index entries for reversions of series

FORMULA

G.f. A(x) satisfies: -1 + Product_{k>=1} (1 + A(x)^k)^k = x.

MATHEMATICA

nmax = 27; Rest[CoefficientList[InverseSeries[Series[-1 + Product[(1 + x^k)^k, {k, 1, nmax}], {x, 0, nmax}], x], x]]

nmax = 27; Rest[CoefficientList[InverseSeries[Series[-1 + Exp[Sum[(-1)^(k + 1) x^k/(k (1 - x^k)^2), {k, 1, nmax}]], {x, 0, nmax}], x], x]]

CROSSREFS

Cf. A007312, A026007, A050393, A176025.

Sequence in context: A019228 A332734 A178134 * A075121 A075108 A265590

Adjacent sequences:  A291486 A291487 A291488 * A291490 A291491 A291492

KEYWORD

sign

AUTHOR

Ilya Gutkovskiy, Aug 24 2017

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 21 05:55 EDT 2020. Contains 337267 sequences. (Running on oeis4.)