A091463 a(n) is the smallest j such that 1/1 + 1/4 + 1/7 + ... + 1/j exceeds n.
4, 52, 1060, 21301, 427873, 8594032, 172615738, 3467079760, 69638158519
Offset: 1
Programs
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Mathematica
s = 0; k = 1; Do[ While[s = N[s + 1/k, 24]; s <= n, k += 3]; Print[k]; k += 3, {n, 1, 7}]
Formula
The next term is approximately the previous term * e^3.
Extensions
Name edited by Jon E. Schoenfield, Dec 20 2019
a(8)-a(9) from Hugo Pfoertner, Dec 27 2019