A004665 Powers of 3 written in base 11. (Next term contains a non-decimal character.)

1, 3, 9, 25, 74, 201, 603, 1709

Offset

0,2

Comments

The next term contains a non-decimal character if such a character (e.g., 'A') is chosen to represent a digit 10, where "digit" means the coefficients in N = Sum_{k>=0} d_k * 11^k. A different "encoding" has to be used to represent such terms in the Data sections of OEIS entries. In order to preserve the terms a(0..7), one could use the two-digit combinations '08' and '18' to encode the digits 8 (the only one not occurring so far) and 10. - M. F. Hasler, Jun 25 2018

Links

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

Mathematica

FromDigits[IntegerDigits[#, 11]]&/@(3^Range[0, 7]) (* Harvey P. Dale, Jul 31 2013  *)

Prog

(PARI) apply( A004665(n)=if(vecmax(n=digits(3^n, 11))>9, Strchr(apply(d->48+d+(d>9)*7, n)), fromdigits(n)), [0..10]) \\ Slightly shorter but slower: {a(n)=iferr(eval(n=Strchr(apply(d->48+d+(d>9)*7, digits(3^n, 11)))), E, n)}. - M. F. Hasler, Jun 25 2018

Crossrefs

Sequence in context: A211298 A138574 A101499 * A196431 A244826 A183111

Adjacent sequences: A004662 A004663 A004664 * A004666 A004667 A004668

Keyword

nonn,base

Author

N. J. A. Sloane

Status

approved