1,3

Numbers m such that A133048(m) = A133500(m);

A133500(a(n)) = A133048(a(n)) = A222493(n);

if m is a term then also its reversal in decimal representation, palindromes are a subsequence, cf. A004086, A002113.

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Some non-palindromic terms:

a(11) = 10: A133500(10) = 1^0 = 1 = A133048(10) = A133048(1) = 1;

a(14) = 24: A133500(24) = 2^4 = 16 = A133048(24) = 4^2;

a(16) = 42: A133500(42) = 4^2 = 16 = A133048(42) = 2^4;

a(25) = 112: A133500(112) = 1^1 * 2 = 2 = A133048(112) = 2^1 * 1;

a(26) = 113: A133500(113) = 1^1 * 3 = 3 = A133048(113) = 3^1 * 1;

a(44) = 213: A133500(213) = 2^1 * 3 = 6 = A133048(213) = 3^1 * 2.

(Haskell)

a221221 n = a221221_list !! (n-1)

a221221_list = filter (\x -> a133500 x == a133048 x) [0..]

Sequence in context: A034704 A276512 A023792 * A178354 A179309 A032946

Adjacent sequences: A221218 A221219 A221220 * A221222 A221223 A221224

nonn,base

Reinhard Zumkeller, May 27 2013

approved