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A196942
a(n) is the prime order of sequence A196941.
1
0, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 2, 1, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 3, 3, 1, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 1, 1, 1, 2, 1, 3, 2, 4, 1, 2, 2, 2, 2, 3, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 2
OFFSET
2,6
COMMENTS
Assuming 1 is the 0th prime, as what in Mathematica: PrimePi[1] = 0.
So far the first occurrence of this sequence agree with A062241 and A045535. Is this a coincidence or a theorem?
EXAMPLE
A196941(3) = 2, which is the first prime number, so a(3) = 1;
MATHEMATICA
FactorSet[seed_] := Module[{fset2, a, l, i}, a = FactorInteger[seed]; l = Length[a]; fset2 = {}; Do[fset2 = Union[fset2, {a[[i]][[1]]}], {i, 1, l}]; fset2]; Table[min = n; Do[r = n - k; s = Union[FactorSet[k], FactorSet[r]]; If[a = s[[Length[s]]]; a < min, min = a], {k, 1, IntegerPart[n/2]}]; PrimePi[min], {n, 2, 88}]
CROSSREFS
Sequence in context: A212185 A270928 A290257 * A184304 A363298 A025909
KEYWORD
nonn,easy
AUTHOR
Lei Zhou, Oct 07 2011
STATUS
approved