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A188425
Position of 2^n in A051037 (5-smooth numbers).
4
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
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
KEYWORD
nonn
AUTHOR
Zak Seidov, Mar 30 2011
STATUS
approved