This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A039999 Number of permutations of digits of n which yield distinct primes. 16
 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}] (* Harvey P. Dale, Jun 26 2011 *) PROG (PARI) for(x=1, 400, print1(permprime(x), ", ")) /* for definition of function permprime cf. link */ \\ Cino Hilliard, Jun 07 2009 (PARI) A039999(n, D=vecsort(digits(n)), S)={forperm(D, p, isprime(fromdigits(Vec(p))) && S++); S} \\ Giving the 2nd arg avoids computing it and increases efficiency when the digits are already known. Must be sorted because forperm() only considers "larger" permutations. - M. F. Hasler, Oct 14 2019 (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] ]; // 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. Cf. A039993 (number of primes embedded in n), A076730 (maximum for n digits), A072857 (record indices: primeval numbers), A134596 (largest with n digits). Cf. A075053 (as A039993 but counted with multiplicity), A134597 (maximum for n digits). Sequence in context: A046810 A323989 A262988 * A069842 A083056 A321100 Adjacent sequences:  A039996 A039997 A039998 * A040000 A040001 A040002 KEYWORD nonn,base,nice AUTHOR EXTENSIONS Contribution of Cino Hilliard edited by Klaus Brockhaus, Jun 15 2009 Edited by M. F. Hasler, Oct 14 2019 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 5 13:26 EST 2019. Contains 329751 sequences. (Running on oeis4.)