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

1,1

Links

Table of n, a(n) for n=1..9.

Formula

The next term is approximately the previous term * e^3.

Mathematica

s = 0; k = 1; Do[ While[s = N[s + 1/k, 24]; s <= n, k += 3]; Print[k]; k += 3, {n, 1, 7}]

Crossrefs

Cf. A002387, A056053, A056054, A091462, A091464.

Sequence in context: A144340 A247020 A059580 * A354253 A354262 A144829

Adjacent sequences: A091460 A091461 A091462 * A091464 A091465 A091466

Keyword

nonn,more

Author

Robert G. Wilson v, Jan 12 2004

Extensions

Name edited by Jon E. Schoenfield, Dec 20 2019

a(8)-a(9) from Hugo Pfoertner, Dec 27 2019

Status

approved