A022874 a(n) = [ a(n-1)/a(1) ] + [ a(n-1)/a(2) ] + ... + [ a(n-1)/a(n-1) ] for n >= 3.

2, 1, 1, 2, 6, 19, 60, 194, 628, 2035, 6597, 21393, 69382, 225031, 729865, 2367255, 7678002, 24902998, 80770936, 261974262, 849693202, 2755914018, 8938593456, 28991634898, 94032120191, 304985891949, 989198096368

Offset

1,1

Links

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

Formula

a(n) ~ c * d^n, where d = 3.243422474587042277724011259031636390127037162673948731178241793178427249639..., c = 0.015782950162188139059124323554918048406538374877378493529663483700401917... - Vaclav Kotesovec, May 22 2019

Mathematica

Clear[a]; a[n_] := a[n] = If[n==1, 2, Sum[Floor[a[n-1]/a[k]], {k, 1, n-1}]]; Table[a[n], {n, 1, 30}] (* Vaclav Kotesovec, May 22 2019 *)

Crossrefs

Cf. A022855, A022858.

Sequence in context: A107042 A134830 A319031 * A022873 A323739 A122160

Adjacent sequences: A022871 A022872 A022873 * A022875 A022876 A022877

Keyword

nonn

Author

Clark Kimberling

Extensions

a(26) corrected by Sean A. Irvine, May 22 2019

Status

approved