A095137 Absolute difference between the product of the first floor(n/2) even-indexed primes and the product of the first floor(n/2) odd-indexed primes.

2, 1, 7, 11, 89, 163, 1597, 3317, 37823, 107413, 1182887, 4232341, 49100059, 184657283, 2329965377, 10114830259, 138903895201, 622143222539, 9382665690241, 44778520855589, 686482057860331, 3598441529151191

Offset: 1

Author

Robert G. Wilson v, May 28 2004

Keywords

• nonn

Examples

			a(5) = 2*5*11 - 3*7 = 89, a(6) = 3*7*13 - 2*5*11 = 163;
a(7) = 2*5*11*17 - 3*7*13 = 1597, a(8) = 3*7*13*19 - 2*5*11*17 = 3317.
		

Crossrefs

Cf. A095134, A000040, A066206, A066205.

Programs

Mathematica

PrimeFactors[n_] := Flatten[ Table[ #[[1]], {1} ] & /@ FactorInteger[n]]; f[n_] := Abs[ Product[ Prime[i], {i, 2, n, 2}] + Product[ Prime[i], {i, 1, n, 2}]]; f[1] = 2; Table[ f[n], {n, 24}]
Join[{2},Table[Abs[Times@@Prime[Range[1,Floor[n/2],2]]-Times@@Prime[Range[ 2,Floor[ n/2 ],2]]],{n,4,45,2}]] (* Harvey P. Dale, Jan 11 2023 *)

Formula

The absolute difference of Product_{j=1..floor(n/2)} p_(2j) (A066206) and Product_{k=1..floor(n/2)} p_(2j-1) (A066205).