The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A126071 Number of bases (2 <= b <= n+1) in which n is a palindrome. 4
 1, 1, 2, 2, 3, 2, 3, 3, 3, 4, 2, 3, 3, 3, 4, 4, 4, 4, 2, 4, 5, 3, 3, 5, 3, 5, 4, 5, 3, 4, 4, 4, 4, 4, 3, 6, 3, 4, 3, 6, 3, 5, 3, 4, 5, 5, 2, 6, 3, 5, 5, 6, 2, 5, 5, 5, 5, 3, 3, 7, 3, 4, 6, 5, 6, 5, 4, 5, 3, 5, 3, 7, 4, 4, 4, 4, 3, 7, 2, 8, 4, 5, 3, 7, 6, 4, 3 (list; graph; refs; listen; history; text; internal format)
 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 Cf. A016026. Cf. A016038, A047811 (related to numbers having 2 bases). Sequence in context: A334686 A057941 A358550 * A338292 A359728 A217865 Adjacent sequences: A126068 A126069 A126070 * A126072 A126073 A126074 KEYWORD nonn,base AUTHOR Paul Richards, Mar 01 2007 EXTENSIONS Extended by T. D. Noe, Oct 04 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 20 01:45 EDT 2024. Contains 372703 sequences. (Running on oeis4.)