A188425 Position of 2^n in A051037 (5-smooth numbers).

1, 2, 4, 7, 12, 19, 27, 38, 52, 68, 87, 110, 137, 167, 201, 240, 284, 332, 386, 446, 511, 582, 660, 745, 836, 934, 1041, 1155, 1277, 1407, 1545, 1692, 1849, 2015, 2190, 2376, 2571, 2777, 2994, 3222, 3461, 3711, 3974, 4249, 4535, 4834, 5147, 5473, 5811, 6164, 6531, 6911, 7306, 7716, 8142, 8582, 9039, 9511, 9999, 10503, 11024, 11563, 12119, 12692, 13283, 13892, 14519

Offset

0,2

Links

Zak Seidov, Table of n, a(n) for n = 0..200

Formula

A051037(a(n)) = 2^n.

a(n) ~ c * n^3, where c = log(2)^2/(6*log(3)*log(5)) = 0.045287775775708... - Vaclav Kotesovec and Amiram Eldar, Sep 22 2024

Example

2^0 = 1 = A051037(1), hence a(0) = 1.
a(25) = 934 because 2^25 = 33554432 = A051037(934).

Crossrefs

Cf. A051037, A188426, A188427 (positions of powers of 3 and 5 in A051037).

Sequence in context: A209616 A192521 A066699 * A087149 A090853 A333311

Adjacent sequences: A188422 A188423 A188424 * A188426 A188427 A188428

Keyword

nonn

Author

Zak Seidov, Mar 30 2011

Status

approved