A147800 Minimal value of A007947(m*(5^n-m)) with m coprime to 5.

2, 6, 22, 42, 222, 366, 2046, 13962, 10626, 79926, 293262

Offset: 1

Author

M. F. Hasler, Nov 13 2008

Keywords

• nonn
• more

Comments

The minima are reached for m values given in A147803.

This is related to the abc conjecture.

All terms of this sequence are even, so one could also consider A147800/2 = 1, 3, 11, 21, 111, 183, 1023, 6981, 5313, 39963, 146631, ...

Crossrefs

Cf. A007947, A147803 (m values), A143702 (analog for 2^n), A147801 (analog for 3^n), A147298 (general case).

Programs

PARI

A147800(n, p=5) = {my(m=n=p^n); for(a=1, (n-1)\2, a%p || next; A007947(n-a)*A007947(a)A007947((n-a)*a)); m; }