A184336 a(n) = n + floor((3*n)^(1/3) - 2/3).

1, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 66, 67, 68, 69, 70, 71

Offset: 1

Author

Robert G. Wilson v, Feb 13 2011

Keywords

• easy
• nonn

Comments

Complement: 2, 8, 19, 37, 65, 104, 157, 224, 310, 414, 540, 689, 863, ..., .

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A007401.

Programs

Maple

A184336:=n->n+floor(-(2/3) + (3*n)^(1/3)); seq(A184336(k), k=1..100); # Wesley Ivan Hurt, Nov 08 2013

Mathematica

f[n_] := n + Floor[-2/3 + (3 n)^(1/3)]; Array[f, 66]
Table[n+Floor[Surd[3n,3]-2/3],{n,70}] (* Harvey P. Dale, Jan 25 2023 *)