A025712 Index of 6^n within sequence of numbers of form 2^i*6^j.

1, 4, 10, 18, 29, 42, 58, 77, 98, 122, 148, 177, 209, 243, 280, 319, 361, 405, 452, 502, 554, 609, 666, 726, 789, 854, 922, 992, 1065, 1140, 1218, 1299, 1382, 1468, 1556, 1647, 1741, 1837, 1936, 2037, 2141, 2247, 2356, 2468, 2582, 2699, 2818, 2940, 3065, 3192

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Positions of zeros in A025636. - R. J. Mathar, Jul 06 2025

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..1000
• Beata Bajorska-Harapińska, Barbara Smoleń, Roman Wituła, On Quaternion Equivalents for Quasi-Fibonacci Numbers, Shortly Quaternaccis, Advances in Applied Clifford Algebras (2019) Vol. 29, 54.

Crossrefs

Cf. A025610.

Programs

Mathematica

With[{n = 6^49}, Position[Union@ Flatten@ Table[2^a * 6^b, {a, 0, Log2@ n}, {b, 0, Log[6, n/2^a]}], ?(IntegerQ@ Log[6, #] &)][[All, 1]]] (* _Michael De Vlieger, Jul 16 2019 *)