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

1,2

Comments

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

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.

Example

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

Crossrefs

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

Sequence in context: A339889 A023809 A046100 * A023757 A115105 A121176

Adjacent sequences: A337135 A337136 A337137 * A337139 A337140 A337141

Keyword

nonn,fini,full

Author

Chun Lok Yiu, Aug 18 2020

Status

approved