A034082 a(n) = least integer m such that the part after the decimal point of the n-th root of m starts with the digit 5.

21, 4, 6, 8, 12, 18, 26, 39, 58, 87, 130, 195, 292, 438, 657, 986, 1478, 2217, 3326, 4988, 7482, 11223, 16835, 25252, 37877, 56816, 85223, 127835, 191752, 287627, 431440, 647160, 970740, 1456110, 2184165, 3276247, 4914370, 7371555, 11057333, 16585999, 24878998, 37318497

Offset

2,1

Links

Paolo Xausa, Table of n, a(n) for n = 2..1000

Formula

For n > 2: a(n) = ceiling((3/2)^n) = A002379(n) + 1. - Henry Bottomley, May 02 2001

Example

a(25) = 25252 -> 25252^(1/25) = 1.{5}000019762083...

Mathematica

A034082[n_] := If[n == 2, 21, Ceiling[(3/2)^n]]; Array[A034082, 50, 2] (* Paolo Xausa, Mar 09 2026 *)

Prog

(Python)
def A034082(n): return (3**n>>n)+1 if n > 2 else 21 # Chai Wah Wu, Sep 21 2022

Crossrefs

Cf. A034062, A034072, A002379, A061418, A061419.

Sequence in context: A040428 A040429 A082128 * A040427 A070988 A358268

Adjacent sequences: A034079 A034080 A034081 * A034083 A034084 A034085

Keyword

nonn,base,easy

Author

Patrick De Geest, Sep 15 1998

Extensions

Definition clarified by N. J. A. Sloane, May 24 2021

More terms from Paolo Xausa, Mar 09 2026

Status

approved