A118598 Palindromes in base 7 (written in base 7).

0, 1, 2, 3, 4, 5, 6, 11, 22, 33, 44, 55, 66, 101, 111, 121, 131, 141, 151, 161, 202, 212, 222, 232, 242, 252, 262, 303, 313, 323, 333, 343, 353, 363, 404, 414, 424, 434, 444, 454, 464, 505, 515, 525, 535, 545, 555, 565, 606, 616, 626, 636, 646, 656, 666, 1001

Offset: 1

Author

Martin Renner, May 08 2006

Keywords

• nonn
• base

Crossrefs

Cf. A029954, A057148, A118594, A118595, A118596, A118597, A118598, A118599, A118600, A002113.

Programs

Mathematica

(* get NextPalindrome from A029965 *) Select[NestList[NextPalindrome, 0, 109], Max@IntegerDigits@# < 7 &] (* Robert G. Wilson v, May 09 2006 *)

Python

from sympy import integer_log
from gmpy2 import digits
def A118598(n):
    if n == 1: return 0
    y = 7*(x:=7**integer_log(n>>1,7)[0])
    return int((s:=digits(n-x,7))+s[-2::-1] if nChai Wah Wu, Jun 14 2024

Extensions

Corrected and extended by Robert G. Wilson v, May 09 2006