A022874 a(n) = [ a(n-1)/a(1) ] + [ a(n-1)/a(2) ] + ... + [ a(n-1)/a(n-1) ] for n >= 3, with initial terms 2,1.
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
Keywords
Programs
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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 *)
Formula
a(n) ~ c * d^n, where d = 3.243422474587042277724011259031636390127037162673948731178241793178427249639..., c = 0.015782950162188139059124323554918048406538374877378493529663483700401917... - Vaclav Kotesovec, May 22 2019
Extensions
a(26) corrected by Sean A. Irvine, May 22 2019
Name clarified by Robert C. Lyons, Feb 11 2025