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A176837 Number of pairs (a, b) of positive integers with a < b such that both a^2 - nb and b^2 - na are squares 3
0, 0, 2, 1, 4, 2, 6, 5, 9, 4, 8, 13, 12, 6, 21, 18, 14, 9, 14, 28, 27 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..21.

EXAMPLE

A176837(3) = 2 because the pairs (5, 8) and (7, 11) have the specified property: 5^2 - 3*8 = 1^2, 8^2 - 3*5 = 7^2; 7^2 - 3*11 = 4^2, 11^2 - 3*7 = 10^2.

CROSSREFS

A176837(n) = A176836(n) - A176835(n)

Sequence in context: A154280 A004795 A161268 * A007690 A239960 A292402

Adjacent sequences:  A176834 A176835 A176836 * A176838 A176839 A176840

KEYWORD

nonn

AUTHOR

Jens Voß, Apr 27 2010

STATUS

approved

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Last modified March 21 01:18 EDT 2019. Contains 321356 sequences. (Running on oeis4.)