

A185953


Number of pairwise coprime triples of positive integers with largest element n (i.e., A015617(n)  A015617(n1)).


6



0, 0, 1, 1, 5, 1, 11, 6, 12, 5, 31, 6, 45, 14, 21, 24, 79, 15, 101, 27, 49, 37, 149, 28, 126, 56, 109, 57, 241, 28, 277, 106, 137, 100, 183, 62, 395, 128, 193, 102, 489, 65, 541, 165, 203, 189, 649, 116, 551, 170, 347, 231, 829, 147, 506, 234, 434, 307, 1027, 119, 1101, 364, 450, 412, 727
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OFFSET

1,5


REFERENCES

Robert Israel, Posting to Sequence Fans Mailing List, Feb 06, 2011


LINKS



MATHEMATICA

a[n_] := Sum[Boole[GCD[a, n] == 1 && GCD[b, n] == 1 && GCD[a, b] == 1], {a, 1, n2}, {b, a+1, n1}]; Array[a, 100] (* JeanFrançois Alcover, Mar 05 2019, from PARI *)


PROG

(PARI) a(n)=sum(a=1, n2, sum(b=a+1, n1, gcd(a, n)==1&&gcd(b, n)==1&&gcd(a, b)==1)) \\ Charles R Greathouse IV, Apr 28 2015


CROSSREFS



KEYWORD



AUTHOR



STATUS

approved



