A221221 - OEIS

%I #12 May 27 2013 10:35:36

%S 0,1,2,3,4,5,6,7,8,9,10,11,22,24,33,42,44,55,66,77,88,99,101,111,112,

%T 113,114,115,116,117,118,119,121,131,141,151,161,171,181,191,202,211,

%U 212,213,214,215,216,217,218,219,222,232,242,252,262,272,282,292

%N Where powerbacks and powertrains coincide.

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

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

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

%H Reinhard Zumkeller, <a href="/A221221/b221221.txt">Table of n, a(n) for n = 1..10000</a>

%e Some non-palindromic terms:

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

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

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

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

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

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

%o (Haskell)

%o a221221 n = a221221_list !! (n-1)

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

%K nonn,base

%O 1,3

%A _Reinhard Zumkeller_, May 27 2013