A340046 Numbers that are the sum of a square s and a fourth power t such that 0 < s < t.

17, 20, 25, 82, 85, 90, 97, 106, 117, 130, 145, 257, 260, 265, 272, 281, 292, 305, 320, 337, 356, 377, 400, 425, 452, 481, 626, 629, 634, 641, 650, 661, 674, 689, 706, 725, 746, 769, 794, 821, 850, 881, 914, 949, 986, 1025, 1066, 1109, 1154, 1201, 1297, 1300, 1305, 1312

Offset

1,1

Links

Table of n, a(n) for n=1..54.

Example

20 is in the sequence since 2^2 + 2^4 = 4 + 16 = 20, where 0 < 4 < 16.

Mathematica

Table[If[Sum[(Floor[i^(1/2)] - Floor[(i - 1)^(1/2)]) (Floor[(n - i)^(1/4)] - Floor[(n - i - 1)^(1/4)]), {i, Floor[(n - 1)/2]}] > 0, n, {}], {n, 1500}] // Flatten

Crossrefs

Cf. A010052.

Sequence in context: A187749 A361169 A034069 * A116037 A081643 A146169

Adjacent sequences: A340043 A340044 A340045 * A340047 A340048 A340049

Keyword

nonn

Author

Wesley Ivan Hurt, Dec 26 2020

Status

approved