OFFSET
1,3
COMMENTS
a(n) >= 1, since n will always have a single "digit" in base n+1.
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000
EXAMPLE
From bases 2 to 9 respectively, 8 can be represented as: 1000, 22, 20, 13, 12, 11, 10, 8. Three of those are symmetrical (22, 11, 8) and so a(8) = 3.
MATHEMATICA
Table[cnt = 0; Do[d = IntegerDigits[n, k]; If[d == Reverse[d], cnt++], {k, 2, n + 1}]; cnt, {n, 100}] (* T. D. Noe, Oct 04 2012 *)
PROG
(PARI) a(n) = sum(k=2, n+1, d = digits(n, k); Vecrev(d) == d); \\ Michel Marcus, Mar 07 2015
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Paul Richards, Mar 01 2007
EXTENSIONS
Extended by T. D. Noe, Oct 04 2012
STATUS
approved