A205956 Distinct primes occurring as not necessarily consecutive subsequences in decimal representation of 39467139.

3, 7, 13, 19, 31, 37, 41, 43, 47, 61, 67, 71, 73, 79, 97, 139, 313, 347, 349, 367, 373, 379, 397, 419, 439, 461, 463, 467, 479, 613, 619, 673, 719, 739, 919, 941, 947, 967, 971, 3413, 3461, 3463, 3467, 3469, 3613, 3671, 3673, 3719, 3739, 3919, 3943, 3947

Offset: 1

Author

Reinhard Zumkeller, Feb 02 2012

Keywords

• nonn
• base
• fini
• full

Comments

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.

Examples

			a(10) = 61        <- ___6_1__;
a(20) = 367       <- 3__67___;
a(30) = 613       <- ___6_13_;
a(40) = 3413      <- 3_4__13_;
a(50) = 3919      <- 39___1_9;
a(60) = 9419      <- _94__1_9;
a(70) = 9719      <- _9__71_9;
a(80) = 39439     <- 394___39;
a(90) = 346139    <- 3_46_139;
a(100) = 3946139  <- 3946_139.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..100 (full sequence)

Crossrefs

Cf. A010051.

Programs

Haskell

import Data.List (subsequences, nub, sort)
a205956 n = a205956_list !! (n-1)
a205956_list = sort $ filter ((== 1) . a010051) $
                      nub $ map read (tail $ subsequences "39467139")