

A127077


a(1)=1. a(n) = a(n1) + (product of the earlier terms {among terms a(1) through a(n1)} which are coprime to n).


1



1, 2, 4, 5, 13, 78, 40638, 40703, 21206263, 11221082003820, 15964509207021745126354079410538220, 15964509207021745126410184714526005
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OFFSET

1,2


LINKS



EXAMPLE

The terms of the sequence, among terms a(1) through a(5), which are coprime to 6 are a(1)=1, a(4)=5 and a(5) = 13. So a(6) = a(5) + 1*5*13 = 78.


MATHEMATICA

f[l_List] := Append[l, l[[ 1]] + Times @@ Select[l, GCD[ #, Length[l] + 1] == 1 &]]; Nest[f, {1}, 15] (* Ray Chandler, Jan 06 2007 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



