A121744 Numbers n such that (1 + Sum[Prime[k],{k,1,n}]) = (1 + A007504[n]) divides primorial number p(n)# = Product[Prime[k],{k,1,n}] = A002110[n].

2, 6, 8, 10, 11, 15, 21, 26, 27, 37, 39, 45, 47, 52, 75, 84, 87, 88, 91, 94, 101, 107, 113, 116, 124, 131, 133, 136, 137, 138, 155, 157, 162, 173, 175, 181, 183, 188, 201, 215, 225, 230, 237, 238, 242, 244, 245, 249, 253, 255, 257, 271, 275, 281, 284, 292, 301

Offset: 1

Author

Alexander Adamchuk, Aug 19 2006

Keywords

• nonn

Comments

Also a(n) is a set of indices n such that A120291[n] = 1. A120291[n] begins {3,1,11,3,29,1,59,1,101,1,1,3,239,47,1,191,21,251,569,64,1,12,25,482,1061,1,1,...}.

Crossrefs

Cf. A007504, A002110, A120291.

Programs

Mathematica

Select[Range[500],Numerator[(1+Sum[Prime[k],{k,1,#1}])/Product[Prime[k],{k,1,#1}]]==1&]