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A281971
Number of sets of exactly n positive integers <= n+8 having a square element sum.
2
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
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
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 03 2017
STATUS
approved