A075675 Sum of next n even interprimes.

4, 18, 74, 182, 358, 746, 1176, 1854, 2650, 3870, 5696, 7358, 9818, 13052, 16134, 19742, 24192, 30048, 36306, 42932, 50954, 59904, 70210, 82646, 93446, 105640, 117558, 131950, 148108, 165772

Offset: 1

Author

Zak Seidov, Sep 24 2002

Keywords

• nonn

Comments

Sum of next n primes in A007468. Sum of next n integer interprimes in A075673. Sum of next n odd interprimes in A075674.

Examples

			a(1) = (3+5)/2 = 4; a(2) = (5+7)/2+(11+13)/2 = 6 + 12 = 18.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A007468, A075673, A075674, A075675.

Programs

Mathematica

ev=Select[Table[(Prime[i]+Prime[i+1])/2, {i, 2, 2000}], EvenQ]; (* sum of next n even interprimes*) i1 := n(n-1)/2+1; i2 := n(n-1)/2+n; A075675=Table[Sum[ev[[i]], {i, i1, i2}], {n, 30}]
Module[{nn=1000,ip,len},ip=Select[Mean/@Partition[Prime[Range[nn]],2,1],EvenQ];len=Length[ip];Total/@TakeList[ip,Range[(Sqrt[1+8*len]-1)/2]]] (* Requires Mathematica version 11 or later *) (* Harvey P. Dale, Jun 30 2020 *)