A281968 Number of sets of exactly n positive integers <= n+5 having a square element sum.

1, 2, 4, 8, 14, 24, 39, 60, 86, 121, 171, 228, 294, 387, 499, 614, 762, 953, 1152, 1362, 1654, 1979, 2280, 2678, 3167, 3628, 4117, 4798, 5498, 6109, 6968, 7967, 8824, 9793, 11127, 12382, 13462, 15088, 16845, 18230, 19981, 22294, 24272, 26047, 28849, 31616

Offset

0,2

Links

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

Formula

a(n) = A281871(n+5,n).

Example

a(2) = 4: {1,3}, {2,7}, {3,6}, {4,5}.
a(3) = 8: {1,2,6}, {1,3,5}, {1,7,8}, {2,3,4}, {2,6,8}, {3,5,8}, {3,6,7}, {4,5,7}.
a(4) = 14: {1,2,4,9}, {1,2,5,8}, {1,2,6,7}, {1,3,4,8}, {1,3,5,7}, {1,4,5,6}, {1,7,8,9}, {2,3,4,7}, {2,3,5,6}, {2,6,8,9}, {3,5,8,9}, {3,6,7,9}, {4,5,7,9}, {4,6,7,8}.

Crossrefs

A diagonal of A281871.

Sequence in context: A053800 A262968 A261203 * A091774 A344741 A280874

Adjacent sequences: A281965 A281966 A281967 * A281969 A281970 A281971

Keyword

nonn

Author

Alois P. Heinz, Feb 03 2017

Status

approved