A127078 - OEIS

A127078

a(0)=1. a(n) = a(n-1) + (product of the earlier terms {among terms a(0) through a(n-1)} which are coprime to n).

1, 2, 3, 5, 20, 26, 31, 483631, 225372046, 17570301566444363246, 17570301566489340929, 16272673148565174391333181067098727985892644426731405243329

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OFFSET

0,2

LINKS

EXAMPLE

The terms of the sequence, among terms a(0) through a(5), which are coprime to 6 are a(0)=1 and a(3)=5. So a(6) = a(5) + 1*5 = 31.

MATHEMATICA

f[l_List] := Append[l, l[[ -1]] + Times @@ Select[l, GCD[ #, Length[l]] == 1 &]]; Nest[f, {1}, 13] (* Ray Chandler, Jan 06 2007 *)

CROSSREFS

KEYWORD

nonn

AUTHOR

Leroy Quet, Jan 04 2007

EXTENSIONS

Extended by Ray Chandler, Jan 06 2007

STATUS

approved