A281971 Number of sets of exactly n positive integers <= n+8 having a square element sum.

1, 3, 7, 20, 49, 110, 227, 435, 786, 1358, 2259, 3621, 5627, 8538, 12655, 18318, 26049, 36487, 50236, 68131, 91412, 121207, 158659, 205768, 264786, 337240, 425738, 534408, 665866, 822789, 1011364, 1237211, 1502645, 1814854, 2184786, 2615980, 3114026, 3695678

Offset

0,2

Links

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

Formula

a(n) = A281871(n+8,n).

Example

a(2) = 7: {1,3}, {1,8}, {2,7}, {3,6}, {4,5}, {6,10}, {7,9}.
a(3) = 20: {1,2,6}, {1,3,5}, {1,4,11}, {1,5,10}, {1,6,9}, {1,7,8}, {2,3,4}, {2,3,11}, {2,4,10}, {2,5,9}, {2,6,8}, {3,4,9}, {3,5,8}, {3,6,7}, {4,5,7}, {4,10,11}, {5,9,11}, {6,8,11}, {6,9,10}, {7,8,10}.

Crossrefs

A diagonal of A281871.

Sequence in context: A111974 A243100 A173400 * A230352 A271894 A066315

Adjacent sequences: A281968 A281969 A281970 * A281972 A281973 A281974

Keyword

nonn

Author

Alois P. Heinz, Feb 03 2017

Status

approved