

A095137


Absolute difference between the product of the first [n/2] even indexed primes and the product of the first [n/2] odd indexed primes.


3



2, 1, 7, 11, 89, 163, 1597, 3317, 37823, 107413, 1182887, 4232341, 49100059, 184657283, 2329965377, 10114830259, 138903895201, 622143222539, 9382665690241, 44778520855589, 686482057860331, 3598441529151191
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


LINKS

Table of n, a(n) for n=1..22.


FORMULA

the absolute difference of the product_{j=2..n, 2} p_j (A066206) and the product_{k=1..n, 2} p_j (A066205).


EXAMPLE

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.


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}]


CROSSREFS

Cf. A095134, A000040, A066206, A066205.
Sequence in context: A100245 A275320 A272931 * A239104 A260259 A141488
Adjacent sequences: A095134 A095135 A095136 * A095138 A095139 A095140


KEYWORD

nonn


AUTHOR

Robert G. Wilson v, May 28 2004


STATUS

approved



