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Distinct primes occurring as not necessarily consecutive subsequences in decimal representation of 39467139.
3

%I #15 Jul 13 2013 12:04:21

%S 3,7,13,19,31,37,41,43,47,61,67,71,73,79,97,139,313,347,349,367,373,

%T 379,397,419,439,461,463,467,479,613,619,673,719,739,919,941,947,967,

%U 971,3413,3461,3463,3467,3469,3613,3671,3673,3719,3739,3919,3943,3947

%N Distinct primes occurring as not necessarily consecutive subsequences in decimal representation of 39467139.

%C 39467139 is the smallest number containing exactly 100 primes: A094535(100) = 39467139, A039995(39467139) = 100; 39467139 itself is not prime: 39467139 = 3*53*89*2789.

%H Reinhard Zumkeller, <a href="/A205956/b205956.txt">Table of n, a(n) for n = 1..100</a> (full sequence)

%e a(10) = 61 <- ___6_1__;

%e a(20) = 367 <- 3__67___;

%e a(30) = 613 <- ___6_13_;

%e a(40) = 3413 <- 3_4__13_;

%e a(50) = 3919 <- 39___1_9;

%e a(60) = 9419 <- _94__1_9;

%e a(70) = 9719 <- _9__71_9;

%e a(80) = 39439 <- 394___39;

%e a(90) = 346139 <- 3_46_139;

%e a(100) = 3946139 <- 3946_139.

%o (Haskell)

%o import Data.List (subsequences, nub, sort)

%o a205956 n = a205956_list !! (n-1)

%o a205956_list = sort $ filter ((== 1) . a010051) $

%o nub $ map read (tail $ subsequences "39467139")

%Y Cf. A010051.

%K nonn,base,fini,full

%O 1,1

%A _Reinhard Zumkeller_, Feb 02 2012