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A376201 Fixed points in A376198.

%I A376201 #40 Oct 15 2024 11:09:51
%S A376201 1,2,3,4,11,12,27,28,59,60,123,124,125,126,255,256,515,516,517,518,
%T A376201 519,520,1043,1044,1045,1046,1047,1048,2099,2100,2101,2102,2103,2104,
%U A376201 2105,2106,2107,2108,2109,2110,4223,4224,4225,4226,4227,4228,8459,8460,16923,16924,16925,16926,33855,33856,67715,67716,67717,67718,67719
%N A376201 Fixed points in A376198.
%C A376201 Conjectures: the terms consist of runs of an even number (>1) of successive numbers that increase by 1 at each step; A376758(n) is one-half of the length of the n-th such run; and the run ends at A376751(n) - 1. - _N. J. A. Sloane_, Oct 07 2024
%H A376201 Michael S. Branicky, <a href="/A376201/b376201.txt">Table of n, a(n) for n = 1..398</a>
%o A376201 (Python)
%o A376201 from itertools import count, islice
%o A376201 from sympy import isprime, nextprime
%o A376201 def agen(): # generator of terms
%o A376201     an, smc, smp = 2, 4, 3
%o A376201     yield from [1, 2]
%o A376201     for n in count(3):
%o A376201         if not isprime(an):
%o A376201             an = smp if an == 2*smp else smc
%o A376201         else:
%o A376201             an = smp if smp < smc else smc
%o A376201         if an == smp: smp = nextprime(smp)
%o A376201         else:
%o A376201             smc += 1
%o A376201             while isprime(smc): smc += 1
%o A376201         if n == an: yield an
%o A376201 print(list(islice(agen(), 59))) # _Michael S. Branicky_, Oct 03 2024
%Y A376201 Cf. A376198-A376200, A376750-A376754, A376758.
%K A376201 nonn
%O A376201 1,2
%A A376201 _N. J. A. Sloane_, Oct 03 2024