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A218021 Shifts 4 places left under Euler transform with a(0)=0 and a(n)=1 for n < 4. 3
0, 1, 1, 1, 1, 1, 2, 3, 5, 7, 12, 18, 30, 47, 78, 125, 209, 341, 571, 946, 1592, 2663, 4503, 7594, 12898, 21891, 37334, 63691, 109039, 186816, 320913, 551829, 950842, 1640149, 2833866, 4901658, 8490019, 14720477, 25553525, 44401638, 77232183, 134457819 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,7

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000

N. J. A. Sloane, Transforms

FORMULA

a(n) ~ c * d^n / n^(3/2), where d = 1.8065918193702780027972... and c = 1.041173202249532389463... . - Vaclav Kotesovec, Jun 23 2014

MAPLE

with(numtheory):

b:= proc(n) option remember; `if`(n=0, 1,

      (add(add(d*a(d), d= divisors(j)) *b(n-j), j=1..n))/n)

    end:

a:= n-> `if`(n<4, signum(n), b(n-4)):

seq(a(n), n=0..45);

MATHEMATICA

b[n_] := b[n] = If[n == 0, 1, (Sum[Sum[d*a[d], {d, Divisors[j]}]*b[n - j], {j, 1, n }])/n]; a[n_] := If[n < 4, Sign[n], b[n - 4]]; Table[a[n], {n, 0, 41}] (* Jean-Fran├žois Alcover, Aug 01 2013, after Alois P. Heinz *)

CROSSREFS

Column k=4 of A144018.

Cf. A316076.

Sequence in context: A013983 A257863 A169986 * A137713 A191385 A143642

Adjacent sequences:  A218018 A218019 A218020 * A218022 A218023 A218024

KEYWORD

nonn,eigen

AUTHOR

Alois P. Heinz, Oct 18 2012

STATUS

approved

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Last modified April 26 04:37 EDT 2019. Contains 322469 sequences. (Running on oeis4.)