A337138 Numbers that cannot be written as the sum of 5 or less squares of composite numbers, allowing repetitions (complement of A055075).

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 69, 70, 71, 73, 74

Offset: 1

Author

Chun Lok Yiu, Aug 18 2020

Keywords

• nonn
• fini
• full

Comments

The largest term of the sequence is a(256) = 1167.

Examples

			52 = 4^2 + 6^2, so 52 is not in the sequence.
		

References

• R. K. Guy, Unsolved Problems In Number Theory, section C20.

Links

• Chun Lok Yiu, Table of n, a(n) for n = 1..256
• R. G. E. Pinch, L. E. Mattics and Emil Grosswald, Solutions to E3262, Amer. Math. Monthly, 97 (No. 3, 1990), 240-242.

Crossrefs

Cf. A002808 (composite numbers), A055075 (complement).