A015639 - OEIS

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A015639

Number of ordered quadruples of integers from [ 2,n ] with no common factors between triples.

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