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A324701
Lexicographically earliest sequence containing 1 and all positive integers n such that the prime indices of n - 1 already belong to the sequence.
12
1, 3, 5, 6, 9, 11, 12, 14, 17, 21, 23, 24, 26, 27, 32, 33, 38, 41, 44, 45, 47, 51, 53, 56, 60, 63, 65, 66, 74, 75, 81, 84, 87, 89, 90, 93, 101, 102, 104, 105, 111, 116, 119, 122, 125, 126, 129, 131, 132, 138, 144, 147, 149, 156, 161, 164, 167, 170, 173, 177
OFFSET
1,2
COMMENTS
A self-describing sequence, similar to A304360.
A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
FORMULA
a(n) = A324700(n) + 1.
MATHEMATICA
aQ[n_]:=Switch[n, 0, False, 1, True, _, And@@Cases[FactorInteger[n-1], {p_, k_}:>aQ[PrimePi[p]]]];
Select[Range[0, 100], aQ]
KEYWORD
nonn
AUTHOR
Gus Wiseman, Mar 10 2019
STATUS
approved