OFFSET
1,1
COMMENTS
Since all consecutive primes, p < q and p greater than 2, are odd, therefore gcd(p-1, q-1) must be even.
EXAMPLE
n=4: a(4) = 24 = gcd(89-1, 97-1) = gcd(p(24)-1, p(25)-1) = 8 = 2n.
MATHEMATICA
a = Table[0, {100}]; p = 3; q = 5; Do[q = Prime[n + 1]; d = GCD[p - 1, q - 1]/2; If[d < 101 && a[[d]] == 0, a[[d]] = n]; b = c, {n, 2, 10^7}]; a
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Jan 31 2002
STATUS
approved