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A376200 Indices where primes appear in A376198.

%I A376200 #10 Oct 04 2024 00:56:16
%S A376200 2,3,9,10,11,23,24,25,26,52,53,54,55,56,57,58,59,110,111,112,113,114,
%T A376200 115,116,117,118,119,120,121,122,231,232,233,234,235,236,237,238,239,
%U A376200 240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,472,473,474,475,476,477,478,479,480,481,482,483,484,485,486,487,488
%N A376200 Indices where primes appear in A376198.
%C A376200 The primes appear in order, so a(n) is also the index of prime(n) in A376198.
%H A376200 Michael S. Branicky, <a href="/A376200/b376200.txt">Table of n, a(n) for n = 1..100000</a>
%o A376200 (Python)
%o A376200 from itertools import count, islice
%o A376200 from sympy import isprime, nextprime
%o A376200 def agen(): # generator of terms
%o A376200     an, smc, smp = 2, 4, 3
%o A376200     for n in count(2):
%o A376200         if not isprime(an):
%o A376200             an = smp if an == 2*smp else smc
%o A376200         else:
%o A376200             yield n
%o A376200             an = smp if smp < smc else smc
%o A376200         if an == smp: smp = nextprime(smp)
%o A376200         else:
%o A376200             smc += 1
%o A376200             while isprime(smc): smc += 1
%o A376200 print(list(islice(agen(), 71))) # _Michael S. Branicky_, Oct 03 2024
%Y A376200 Cf. A376198, A376199, A376201, A376750-A376754.
%K A376200 nonn
%O A376200 1,1
%A A376200 _N. J. A. Sloane_, Oct 03 2024