A130075 a(n) = (5^p - 3^p - 2^p)/p, where p = prime(n).

6, 30, 570, 10830, 4422630, 93776970, 44871187170, 1003806502230, 518297165370030, 6422911941109705770, 150213298561349961630, 1966475018690546370358170, 1109139879321302763891656370

Offset: 1

Author

Alexander Adamchuk, May 06 2007

Keywords

• nonn

Comments

p divides 5^p - 3^p - 2^p = A130072(p) for prime p.

p^(k+1) divides A130072(p^k) for prime p = {2,3,5,19} = A130076(n) and all k>0.

2 divides a(n). 3 divides a(n). 5 divides a(n) for n>1. 19 divides a(n) for n>2. 19^2 divides a(n) for n in A091178(n) or prime(n) in A002476.

Crossrefs

Cf. A130072, A130073, A130074, A130076, A091178, A002476.

Programs

Mathematica

Table[(5^Prime[n]-3^Prime[n]-2^Prime[n])/Prime[n],{n,1,20}]
(5^#-3^#-2^#)/#&/@Prime[Range[20]] (* Harvey P. Dale, May 02 2012 *)

Formula

a(n) = (5^prime(n) - 3^prime(n) - 2^prime(n))/prime(n).

a(n) = A130072(prime(n))/prime(n).