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%I #10 Mar 26 2024 07:54:54
%S 8524807,18381361,18575041,19180817,21312019,31984321,34099231,
%T 40357021,44206633,44839273,48499459,51148847,51444961,51884467,
%U 54144121,57129613,57780487,58293601,61378571,65578901,66786721,66787873
%N Class 11+ primes.
%D R. K. Guy, Unsolved Problems in Number Theory, A18.
%H R. J. Mathar, <a href="/A081639/b081639.txt">Table of n, a(n) for n = 1..108</a>
%p For Maple program see Mathar link in A005105.
%t PrimeFactors[n_Integer] := Flatten[ Table[ #[[1]], {1}] & /@ FactorInteger[n]]; f[n_Integer] := Block[{m = n}, If[m == 0, m = 1, While[ IntegerQ[m/2], m /= 2]; While[ IntegerQ[m/3], m /= 3]]; Apply[Times, PrimeFactors[m] + 1]]; ClassPlusNbr[n_] := Length[ NestWhileList[f, n, UnsameQ, All]] - 3; Prime[ Select[ Range[150000], ClassPlusNbr[ Prime[ # ]] == 11 &]]
%Y Cf. A005113, A005105 - A005108, A081633 - A081638, A084071, A090468.
%K nonn
%O 1,1
%A _Robert G. Wilson v_, Mar 20 2003
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