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A281965 Number of sets of exactly n positive integers <= n+2 having a square element sum. 2
1, 1, 1, 2, 2, 2, 3, 4, 3, 3, 5, 4, 4, 5, 7, 5, 5, 9, 6, 6, 8, 9, 7, 7, 13, 8, 8, 12, 11, 9, 10, 15, 10, 10, 16, 13, 11, 14, 17, 12, 12, 20, 14, 13, 18, 19, 14, 15, 24, 15, 15, 22, 20, 16, 19, 26, 17, 17, 27, 20, 18, 23, 27, 19, 19, 33, 20, 20, 28, 27, 21, 23 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

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

FORMULA

a(n) = A281871(n+2,n).

EXAMPLE

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

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

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

CROSSREFS

A diagonal of A281871.

Sequence in context: A178065 A057748 A057747 * A228074 A152803 A187181

Adjacent sequences:  A281962 A281963 A281964 * A281966 A281967 A281968

KEYWORD

nonn,look

AUTHOR

Alois P. Heinz, Feb 03 2017

STATUS

approved

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Last modified October 22 05:29 EDT 2019. Contains 328315 sequences. (Running on oeis4.)