A305553 Numbers that are not the sum of 2 squares and a 4th power.

7, 12, 15, 22, 23, 28, 31, 39, 43, 44, 47, 55, 60, 63, 67, 70, 71, 76, 78, 79, 87, 92, 93, 95, 103, 108, 111, 112, 119, 124, 127, 135, 140, 143, 151, 156, 159, 167, 168, 172, 175, 177, 183, 184, 188, 191, 192, 199, 204, 207, 214, 215, 220, 223, 231, 236

Offset

1,1

Comments

Numbers of the form 4*A017101(k) are terms of this sequence.

m is a term iff 16m is also.

Links

Table of n, a(n) for n=1..56.

W. Jagy and I. Kaplansky, Sums of Squares, Cubes and Higher Powers, Experimental Mathematics, vol. 4 (1995) pp. 169-173.

Mathematica

n=239;
t=Union@Flatten@Table[x^2+y^2+z^4, {x, 0, n^(1/2)}, {y, x, (n-x^2)^(1/2)}, {z, 0, (n-x^2-y^2)^(1/4)}];
Complement[Range[0, n], t]

Crossrefs

Subsequence of A000037, A140823 and A022544.

A004215 and A214891 are subsequences.

Cf. A017101, A022552.

Sequence in context: A210254 A071780 A353219 * A338103 A190720 A295625

Adjacent sequences: A305550 A305551 A305552 * A305554 A305555 A305556

Keyword

nonn

Author

XU Pingya, Jun 20 2018

Status

approved