A177697 Sums of 3 distinct primorials.

9, 33, 37, 38, 213, 217, 218, 241, 242, 246, 2313, 2317, 2318, 2341, 2342, 2346, 2521, 2522, 2526, 2550, 30033, 30037, 30038, 30061, 30062, 30066, 30241, 30242, 30246, 30270, 32341, 32342, 32346, 32370, 32550, 510513, 510517, 510518, 510541, 510542

Offset: 1

Author

Jonathan Vos Post, May 11 2010

Keywords

• easy
• nonn

Comments

This is to numbers that are the sum of 3 different primes (A124867) as primorials (A002110) are to primes (A000040). The subsequence of primes among these sums of 3 distinct primorials begins: 37, 241, 2341, 2521, 30241, 32341, 512821, 540541.

Examples

			9 = 6+2+1
33 = 30+2+1
37 = 30+6+1
38 = 30+6+2
213 = 210+2+1
		

Crossrefs

Cf. A000040, A002110, A006862, A038609, A124867, A177689.

Programs

Mathematica

Take[Total/@Subsets[Join[{1},FoldList[Times,Prime[Range[10]]]],{3}]// Union,40] (* Harvey P. Dale, Nov 07 2017 *)

Formula

{a(n)} = {A002110(i) + A002110(j) + A002110(k) for i =/= j, i =/= k, j =/= k}.