A082866 a(1)=1, a(2)=2, otherwise a(n) is the sum of the preceding terms a(j), 1<=j<n, where gcd(n,j)=1.

1, 2, 3, 4, 10, 11, 31, 45, 93, 128, 328, 370, 1026, 1461, 2898, 4390, 10801, 12197, 33799, 46082, 96616, 145278, 355574, 401570, 1063600, 1563754, 3226314, 4694447, 11660833, 12062393, 35384059, 51835986, 106656033, 158481218, 369773689

Offset

1,2

Comments

It appears that log(a(n))/n approaches a constant, approximately 0.5815, as n -> infinity. - Robert Israel, Aug 05 2014

Links

Robert Israel, Table of n, a(n) for n = 1..3560

Example

a(6)=11 as gcd(6,2)=2, gcd(6,3)=3 and gcd(6,4)=2. So a(6)=a(1)+a(5)=1+10=11.

Maple

A[1]:= 1: A[2]:= 2:
for n from 3 to 100 do
A[n]:= add(A[j], j=select(t -> igcd(t, n)=1, [$1..n]));
od:
seq(A[n], n=1..100); # Robert Israel, Aug 05 2014

Prog

(PARI) { v=vector(100, i, 0); v[1]=1; v[2]=2; print1("1, 2, "); for (i=3, 100, for (j=1, i-1, if (gcd(i, j) == 1, v[i]+=v[j])); print1(v[i]", ")) }

Crossrefs

Sequence in context: A352148 A259561 A087460 * A085701 A051627 A023725

Adjacent sequences: A082863 A082864 A082865 * A082867 A082868 A082869

Keyword

nonn

Author

Jon Perry, May 24 2003

Status

approved