cp's OEIS Frontend

A324699 Lexicographically earliest sequence of positive integers whose prime indices minus 1 already belong to the sequence.

%I A324699 #8 Mar 11 2019 09:37:20
%S A324699 1,3,7,9,19,21,27,29,49,57,63,71,79,81,87,107,113,133,147,171,189,203,
%T A324699 213,229,237,243,261,271,311,321,339,343,359,361,399,409,421,441,457,
%U A324699 497,513,551,553,567,593,609,619,639,687,711,729,749,757,783,791,813
%N A324699 Lexicographically earliest sequence of positive integers whose prime indices minus 1 already belong to the sequence.
%C A324699 A self-describing sequence, similar to A304360.
%C A324699 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.
%F A324699 a(n) = A306719(n) - 1.
%e A324699 The sequence of terms together with their prime indices begins:
%e A324699     1: {}
%e A324699     3: {2}
%e A324699     7: {4}
%e A324699     9: {2,2}
%e A324699    19: {8}
%e A324699    21: {2,4}
%e A324699    27: {2,2,2}
%e A324699    29: {10}
%e A324699    49: {4,4}
%e A324699    57: {2,8}
%e A324699    63: {2,2,4}
%e A324699    71: {20}
%e A324699    79: {22}
%e A324699    81: {2,2,2,2}
%e A324699    87: {2,10}
%e A324699   107: {28}
%e A324699   113: {30}
%e A324699   133: {4,8}
%e A324699   147: {2,4,4}
%e A324699   171: {2,2,8}
%e A324699   189: {2,2,2,4}
%t A324699 aQ[n_]:=Switch[n,0,False,1,True,_,And@@Cases[FactorInteger[n],{p_,k_}:>aQ[PrimePi[p]-1]]];
%t A324699 Select[Range[100],aQ]
%Y A324699 Prime indices are A306719.
%Y A324699 Cf. A000002, A000720, A001222, A001462, A007097, A055396, A061395, A079000, A079254, A109298, A112798, A276625, A277098, A304360, A306719.
%Y A324699 Cf. A324694, A324695, A324696, A324697, A324698, A324700, A324701, A324702, A324703, A324704, A324705.
%K A324699 nonn
%O A324699 1,2
%A A324699 _Gus Wiseman_, Mar 10 2019