A147801 Minimal value of A007947(m*(3^n-m)) with m coprime to 3.

2, 2, 10, 10, 22, 110, 278, 238, 1054, 1342, 11066, 6118, 18734, 107030, 557270, 163030, 1440430, 2195110, 11016290, 3641210, 23250370, 38188766

Offset: 1

Author

M. F. Hasler, Nov 13 2008

Keywords

• nonn
• more

Comments

Related to the abc conjecture. The minima are reached for m values given in A147802.

All terms of this sequence are even, so one could also consider A147801/2 = 1, 1, 5, 5, 11, 55, 139, 119, 527, 671, 5533, 3059, 9367, 53515, 278635, 81515, ...

Crossrefs

Cf. A007947, A147298 (general case), A143702 (analog for 2^n), A147800 (analog for 5^n), A147802.

Programs

PARI

A147801(n, p=3) = {my(m=n=p^n); for(x=1, (n-1)\2, x%p || next; A007947(n-x)*A007947(x)A007947((n-x)*x)); m; }

Extensions

a(17)-a(22) from Jinyuan Wang, Aug 11 2020