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A015639 Number of ordered quadruples of integers from [ 2,n ] with no common factors between triples. 0
0, 1, 3, 14, 20, 56, 86, 148, 198, 360, 438, 713, 884, 1157, 1433, 2069, 2365, 3262, 3766, 4604, 5331, 6944, 7684, 9527, 10777, 12737, 14229, 17502, 18812, 22809, 25255, 28782, 31654, 36484, 39078, 45912, 49983, 55894, 60145, 69494 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,3

LINKS

Table of n, a(n) for n=2..41.

CROSSREFS

Sequence in context: A108933 A271384 A108420 * A019000 A305090 A071836

Adjacent sequences:  A015636 A015637 A015638 * A015640 A015641 A015642

KEYWORD

nonn

AUTHOR

Olivier Gérard

STATUS

approved

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Last modified November 13 17:34 EST 2019. Contains 329106 sequences. (Running on oeis4.)