A250545 Numbers of the form 4^x + y^4 with x, y >= 0.

1, 2, 4, 5, 16, 17, 20, 32, 64, 65, 80, 82, 85, 97, 145, 256, 257, 260, 272, 320, 337, 512, 626, 629, 641, 689, 881, 1024, 1025, 1040, 1105, 1280, 1297, 1300, 1312, 1360, 1552, 1649, 2320, 2402, 2405, 2417, 2465, 2657, 3425, 4096, 4097, 4100

Offset

1,2

Comments

No terms are divisible by 3, 7 or 11.

Subsequence of A001481 and A250482.

Links

Table of n, a(n) for n=1..48.

Example

17 is in this sequence because 4^0+2^4 = 4^2+1^4=17.
82 is in this sequence because 4^0+3^4 = 82.

Mathematica

nn=10; Union[Select[Flatten[Table[4^x + y^4, {x, 0, nn}, {y, 0, nn}]], #<=nn^4 &]]

Crossrefs

Cf. A001481, A002645.

Cf. similar sequences listed in A250482.

Sequence in context: A071316 A056401 A056406 * A070917 A038757 A377142

Adjacent sequences: A250542 A250543 A250544 * A250546 A250547 A250548

Keyword

nonn,less

Author

Vincenzo Librandi, Nov 26 2014

Status

approved