A281966 Number of sets of exactly n positive integers <= n+3 having a square element sum.

1, 2, 2, 3, 5, 6, 7, 10, 13, 14, 16, 21, 25, 24, 31, 37, 37, 40, 50, 55, 51, 64, 74, 69, 77, 92, 95, 89, 111, 122, 110, 127, 146, 145, 139, 171, 181, 161, 191, 213, 202, 203, 243, 250, 222, 270, 292, 264, 285, 328, 326, 296, 362, 381, 335, 383, 425, 407, 388

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Formula

a(n) = A281871(n+3,n).

Example

a(3) = 3: {1,2,6}, {1,3,5}, {2,3,4}.
a(4) = 5: {1,2,6,7}, {1,3,5,7}, {1,4,5,6}, {2,3,4,7}, {2,3,5,6}.
a(5) = 6: {1,2,3,4,6}, {1,3,6,7,8}, {1,4,5,7,8}, {2,3,5,7,8}, {2,4,5,6,8}, {3,4,5,6,7}.

Crossrefs

A diagonal of A281871.

Sequence in context: A218933 A266746 A096981 * A276431 A308272 A035541

Adjacent sequences: A281963 A281964 A281965 * A281967 A281968 A281969

Keyword

nonn,look

Author

Alois P. Heinz, Feb 03 2017

Status

approved