A226277 Numbers m of the form u^v where u and v are digits in decimal representation of m.

1, 25, 3125, 4096, 15625, 19683, 46656, 59049, 78125, 117649, 279936, 1953125, 4782969, 5764801, 10077696, 387420489

Offset: 1

Author

Reinhard Zumkeller, Jul 09 2013

Keywords

• nonn
• base
• fini
• full

Comments

a(n) occurs in a(n)-th row of table A226272.

Examples

			a(1) = 1 = 1^1;
a(2) = 25 = 5^2;
a(3) = 3125 = 5^5;
a(4) = 4096 = 4^6;
a(5) = 15625 = 5^6;
a(6) = 19683 = 3^9;
a(7) = 46656 = 6^6;
a(8) = 59049 = 9^5;
a(9) = 78125 = 5^7;
a(10) = 117649 = 7^6;
a(11) = 279936 = 6^7;
a(12) = 1953125 = 5^9;
a(13) = 4782969 = 9^7;
a(14) = 5764801 = 7^8;
a(15) = 10077696 = 6^9;
a(16) = 387420489 = 9^9.
256 = 2^8 = 4^4 is not a term, as neither 8 nor 4 occur in 256.
		

Programs

Haskell

import Data.List (sort)
a226277 n = a226277_list !! (n-1)
a226277_list = sort [w | u <- [0..9], v <- [0..9], let w = u ^ v,
   "0123456789" !! u `elem` show w, "0123456789" !! v `elem` show w]