OFFSET
1,1
COMMENTS
a(n) is also the smallest positive integer such that the prime number order of p3 has to be n or larger when a(n) is written as a(n) = p1^m1 * p2^m2 * p3^m3 + p1^n1 * p2^n2 * p3^n3, where p1 < p2 < p3 are prime numbers and m1,m2,m3 and n1,n2,n3 are integers greater than or equal to zero.
LINKS
Lei Zhou, Table of n, a(n) for n = 1..186
EXAMPLE
MATHEMATICA
max = 46; res = Table[0, {i, 1, max}]; i = 1; ct = 0; While[ct < max, i++; ref = i; Do[k = i - j; fj = Transpose[FactorInteger[j]][[1]]; fk = Transpose[FactorInteger[k]][[1]]; fpls = Union[fj, fk]; lf = Length[fpls]; If[lf <= 3, cd = fpls[[lf]]; If[cd < ref, ref = cd]], {j, Ceiling[i/2], i}]; tag = PrimePi[ref]; If[tag <= max, If[res[[tag]] == 0, res[[tag]] = i; ct++]]]; res
CROSSREFS
KEYWORD
nonn
AUTHOR
Lei Zhou, May 20 2013
STATUS
approved