A226810 Numbers of the form 4^j + 5^k, for j and k >= 0.

2, 5, 6, 9, 17, 21, 26, 29, 41, 65, 69, 89, 126, 129, 141, 189, 257, 261, 281, 381, 626, 629, 641, 689, 881, 1025, 1029, 1049, 1149, 1649, 3126, 3129, 3141, 3189, 3381, 4097, 4101, 4121, 4149, 4221, 4721, 7221, 15626, 15629, 15641, 15689, 15881, 16385, 16389

Offset: 1

Author

T. D. Noe, Jun 19 2013

Keywords

• nonn

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A004050 (2^j + 3^k), A226806-A226832 (cases to 8^j + 9^k).

Programs

Mathematica

a = 4; b = 5; mx = 20000; Union[Flatten[Table[a^n + b^m, {m, 0, Log[b, mx]}, {n, 0, Log[a, mx - b^m]}]]]