A004668 Powers of 3 written in base 26. (Next term contains a non-decimal digit.)

1, 3, 9, 11, 33, 99, 121, 363

Offset

0,2

Comments

Aliquot divisors of 1089. - Omar E. Pol, Jun 10 2014

The above comment refers to the first 8 terms only. The next term would contain a digit 18, commonly coded as I, if A, B, ... are used for digits > 9. But this does not mean that the sequence is finite. Many other encodings of digits > 9 are conceivable (e.g., using 000, 100, 110, ..., 250 for digits 0, 10, 11, ..., 25). - M. F. Hasler, Jun 22 2018

Links

Table of n, a(n) for n=0..7.

Mathematica

Select[Divisors[1089], # < 1089 &] (* Wesley Ivan Hurt, Jun 13 2014 *)

Prog

(PARI) fordiv(1089, d, (d<1089) && print1(d, ", ")) \\ Michel Marcus, Jun 14 2014
(PARI) divisors(1089)[^-1] \\ M. F. Hasler, Jun 22 2018
(PARI) apply( A004668(n, b=26, m=3)=fromdigits(digits(m^n, b)), [0..8]) \\ This implements one possible continuation of the sequence beyond n = 7: write digits in decimal and carry over (so 363*3 = 9I9[26] -> 9*100 + 18*10 + 9 = 1089). - M. F. Hasler, Jun 22 2018

Crossrefs

Cf. A000244, A004656, A004658, A004659, ..., A004667: powers of 3 in base 10, 2, 4, 5, ..., 13.

Cf. A000079, A004643, ..., A004655: powers of 2 written in base 10, 4, 5, ..., 16.

Sequence in context: A226477 A027894 A249647 * A239661 A106305 A135365

Adjacent sequences: A004665 A004666 A004667 * A004669 A004670 A004671

Keyword

nonn,base

Author

N. J. A. Sloane, Dec 11 1996

Status

approved