A050390 - OEIS

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A050390

Exponential reversion of divisor function A000005.

1, -2, 10, -83, 968, -14550, 267657, -5823342, 146255131, -4164222891, 132539992770, -4663220787205, 179712285498419, -7528614819216452, 340644924343427080, -16555539553909999044, 860131362806819785898

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..17.

N. J. A. Sloane, Transforms

Index entries for reversions of series

FORMULA

E.g.f. A(x) satisfies: A(x) = x - Sum_{k>=2} d(k) * A(x)^k / k!. - Ilya Gutkovskiy, Apr 22 2020

PROG

(PARI) seq(n)= Vec(serlaplace(serreverse(sum(k=1, n, numdiv(k)*x^k/k!) + O(x*x^n)))); \\ Michel Marcus, Apr 21 2020

CROSSREFS

Cf. A000005, A050389.

Sequence in context: A296667 A003093 A006679 * A298690 A101878 A121194

Adjacent sequences: A050387 A050388 A050389 * A050391 A050392 A050393

KEYWORD

sign

AUTHOR

Christian G. Bower, Nov 15 1999

STATUS

approved