OFFSET
1,7
COMMENTS
This is the k value of A103785. Conjecture: sequence is defined for all n>=1.
EXAMPLE
MATHEMATICA
nmax = 2^2048; npd = 2; n = 2; npd = npd*Prime[n]; While[npd < nmax, tn = 0; tt = 1; cp = npd/tt + tt; While[(IntegerQ[cp]) && (! (PrimeQ[cp])), tn = tn + 1; tt = 1; k1 = tn; o = 1; While[k1 > 0, k2 = Mod[k1, 2]; If[k2 == 1, tt = tt*Prime[o]]; k1 = (k1 - k2)/2; o = o + 1]; cp = npd/tt + tt]; Print[tn]; n = n + 1; npd = npd*Prime[n]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Lei Zhou, Feb 15 2005
STATUS
approved