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A281969 Number of sets of exactly n positive integers <= n+6 having a square element sum. 2
1, 2, 5, 11, 23, 43, 74, 124, 197, 296, 434, 627, 875, 1188, 1600, 2128, 2755, 3522, 4511, 5661, 6983, 8637, 10610, 12781, 15343, 18497, 21937, 25751, 30416, 35702, 41266, 47772, 55531, 63578, 72405, 83101, 94662, 106544, 120507, 136663, 152742, 170490, 191873 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

FORMULA

a(n) = A281871(n+6,n).

EXAMPLE

a(4) = 23: {1,2,3,10}, {1,2,4,9}, {1,2,5,8}, {1,2,6,7}, {1,3,4,8}, {1,3,5,7}, {1,4,5,6}, {1,5,9,10}, {1,6,8,10}, {1,7,8,9}, {2,3,4,7}, {2,3,5,6}, {2,4,9,10}, {2,5,8,10}, {2,6,7,10}, {2,6,8,9}, {3,4,8,10}, {3,5,7,10}, {3,5,8,9}, {3,6,7,9}, {4,5,6,10}, {4,5,7,9}, {4,6,7,8}.

MATHEMATICA

Table[Count[Subsets[Range[n+6], {n}], _?(IntegerQ[Sqrt[Total[#]]]&)], {n, 0, 50}] (* Harvey P. Dale, Aug 21 2017 *)

CROSSREFS

A diagonal of A281871.

Sequence in context: A062475 A186265 A225947 * A124920 A064934 A227637

Adjacent sequences:  A281966 A281967 A281968 * A281970 A281971 A281972

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Feb 03 2017

STATUS

approved

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Last modified October 14 17:43 EDT 2019. Contains 328022 sequences. (Running on oeis4.)