A065531 - OEIS

%I #34 Oct 10 2020 12:15:32

%S 1,0,1,1,2,1,2,2,2,3,1,2,2,2,3,3,3,3,1,3,4,2,2,4,2,4,3,4,2,3,3,3,3,3,

%T 2,5,2,3,2,5,2,4,2,3,4,4,1,5,2,4,4,5,1,4,4,4,4,2,2,6,2,3,5,4,5,4,3,4,

%U 2,4,2,6,3,3,3,3,2,6,1,7,3,4,2,6,5,3,2,5,2,5,4,5,4,2,2,6,2,5,4,7,2,4,1,6,6

%N Number of palindromes in all base b representations for n, for 2<=b<=n.

%C a(1) = 1 by convention, which makes this sequence different from A135551.

%C Index of first occurrence of k in A037183. - _Robert G. Wilson v_, Oct 27 2014

%H Robert G. Wilson v, <a href="/A065531/b065531.txt">Table of n, a(n) for n = 1..1000</a>

%t palindromicBases[n_] := Module[{p}, Table[p = IntegerDigits[n, b]; If[ p == Reverse[p], {b, p}, Sequence @@ {}], {b, 2, n - 1}]]; Table[ Length[ palindromicBases[n]], {n, 105}] (* _Robert G. Wilson v_, May 12 2005 *)

%Y Cf. A016038, A047811, A037183, A107129.

%Y Essentially the same as A135551.

%K easy,nonn,base

%O 1,5

%A _Naohiro Nomoto_, Dec 02 2001