A025699 Index of 3^n within sequence of numbers of form 3^i*8^j (A025615).

1, 2, 4, 6, 9, 12, 16, 20, 25, 30, 36, 42, 49, 56, 64, 72, 81, 90, 100, 111, 122, 134, 146, 159, 172, 186, 200, 215, 230, 246, 262, 279, 296, 314, 332, 351, 371, 391, 412, 433, 455, 477, 500, 523, 547, 571, 596, 621, 647, 673, 700, 727, 755, 784, 813, 843, 873, 904, 935

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Not same as A002620.

The first 19 positive terms are the same, then a(20) = 111 while A002620(21) = 110. - Bernard Schott, Dec 31 2021

Positions of zeros in A025672. - R. J. Mathar, Jul 06 2025

Crossrefs

Cf. A002620, A003586, A025615, A025728 (similar for 8^n).

Formula

A025615(a(n)) = 3^(n-1). - Bernard Schott, Dec 27 2021