A141517 A141498(n)/A027760(n).

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 23, 1, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 47, 1, 1, 1, 1, 1, 1, 1, 1, 1, 23, 1, 71, 73, 1, 1, 1, 5, 1, 7, 431, 1, 1, 1, 1, 97, 1, 1, 1, 1, 1, 1, 23, 1, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 47, 1, 1, 1, 1, 1, 601, 1, 23, 1, 1, 5, 1, 1, 167, 7, 1, 431, 1, 1, 1, 1, 1, 1, 1, 1, 191, 193, 1

Offset: 1

Author

Paul Curtz, Aug 11 2008

Keywords

• nonn

Comments

Composite entries are a(100)=25, a(120)=1205, a(144)=55969, a(156)=4069 etc.

Programs

Maple

A010696 := proc(n) op( (n mod 2)+1,[2,6]) ; end: A086892 := proc(n) gcd(2^n-1,3^n-1) ; end:
A141498 := proc(n) A010696(n-1)* A086892(n) ; end: A027760 := proc(n) local s, p; s := 0 ; p := 2; while p <= n+1 do if n mod (p-1) = 0 then s := s+1/p; fi; p := nextprime(p) ; od: denom(s) ; end:
A141517 := proc(n) A141498(n)/A027760(n) ; end: seq(A141517(n),n=1..120) ; # R. J. Mathar, Sep 03 2009

Extensions

Offset modified, extended by R. J. Mathar, Sep 03 2009