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 A039999 Number of permutations of digits of n which denote primes. 14
 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 2, 1, 0, 1, 2, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 2, 1, 0, 1, 1, 0, 2, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 2, 0, 2, 1, 0, 1, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 2, 1, 0, 0, 2, 0, 3, 2, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,13 COMMENTS Consider all k! permutations of digits of a k-digit number n, discard initial zeros, count distinct primes. LINKS T. D. Noe, Table of n, a(n) for n=1..10000 C. Hilliard, PARI program. EXAMPLE a(20)=1, since from {02, 20} we get {2,20} and only 2 is prime. From 107 we get 4 primes: (0)17, (0)71, 107 and 701; so a(107) = 4. MATHEMATICA Table[Count[FromDigits/@Permutations[IntegerDigits[n]], _?PrimeQ], {n, 110}] (* From Harvey P. Dale, June 26 2011 *) PROG (PARI) for(x=1, 400, print1(permprime(x), ", ")) /* for definition of function permprime cf. link */ [From Cino Hilliard (hillcino368(AT)hotmail.com), Jun 07 2009] (MAGMA) [ #[ s: s in Seqset([ Seqint([m(p[i]):i in [1..#x] ], 10): p in Permutations(Seqset(x)) ]) | IsPrime(s) ] where m is map< x->y | [:i in [1..#x] ] > where x is [1..#y] where y is Intseq(n, 10): n in [1..120] ]; [From Klaus Brockhaus, Jun 15 2009] (Haskell) import Data.List (permutations, nub) a039999 n = length \$ filter ((== 1) . a010051)                    (map read (nub \$ permutations \$ show n) :: [Integer]) -- Reinhard Zumkeller, Feb 07 2011 CROSSREFS Cf. A046810. Sequence in context: A170958 A178651 A046810 * A069842 A083056 A061896 Adjacent sequences:  A039996 A039997 A039998 * A040000 A040001 A040002 KEYWORD nonn,base,nice,easy AUTHOR EXTENSIONS Contribution of C. Hilliard edited by Klaus Brockhaus, Jun 15 2009 STATUS approved

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