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A376199 Index where n appears in A376198.

%I A376199 #9 Oct 04 2024 00:55:42
%S A376199 1,2,3,4,9,5,10,6,7,8,11,12,23,13,14,15,24,16,25,17,18,19,26,20,21,22,
%T A376199 27,28,52,29,53,30,31,32,33,34,54,35,36,37,55,38,56,39,40,41,57,42,43,
%U A376199 44,45,46,58,47,48,49,50,51,59,60,110,61,62,63,64,65,111,66,67,68,112,69,113,70,71,72,73,74,114,75,76,77,115,78,79
%N A376199 Index where n appears in A376198.
%H A376199 Michael S. Branicky, <a href="/A376199/b376199.txt">Table of n, a(n) for n = 1..100000</a>
%o A376199 (Python)
%o A376199 from itertools import count, islice
%o A376199 from sympy import isprime, nextprime
%o A376199 def agen(): # generator of terms
%o A376199     an, smc, smp, adict, n = 2, 4, 3, {1: 1, 2: 2}, 1
%o A376199     for k in count(3):
%o A376199         if not isprime(an):
%o A376199             an = smp if an == 2*smp else smc
%o A376199         else:
%o A376199             an = smp if smp < smc else smc
%o A376199         if an == smp: smp = nextprime(smp)
%o A376199         else:
%o A376199             smc += 1
%o A376199             while isprime(smc): smc += 1
%o A376199         if an not in adict: adict[an] = k
%o A376199         while n in adict: yield adict[n]; n += 1
%o A376199 print(list(islice(agen(), 85))) # _Michael S. Branicky_, Oct 03 2024
%Y A376199 Cf. A376198, A376200-A376201, A376750-A376754.
%K A376199 nonn
%O A376199 1,2
%A A376199 _N. J. A. Sloane_, Oct 03 2024