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A046810
Number of anagrams of n that are primes.
18
0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 2, 1, 0, 1, 2, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 2, 1, 0, 1, 1, 0, 2, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 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, 1, 0, 1, 1, 0, 1, 2, 0
OFFSET
1,13
COMMENTS
An anagram of a k-digit number is one of the k! permutations of the digits that does not begin with 0.
LINKS
EXAMPLE
107 has 2 prime anagrams: 107 and 701 (but not 017 or 071); so a(107) = 2.
MATHEMATICA
Table[Count[FromDigits/@Select[Permutations[IntegerDigits[n]], First[#] != 0&], _?(PrimeQ[#]&)], {n, 110}] (* Harvey P. Dale, Aug 24 2011 *)
PROG
(Haskell)
import Data.List (permutations, nub)
a046810 n = length $ filter ((== 1) . a010051)
$ map read (nub $ filter ((> '0') . head)
$ permutations $ show n)
-- Reinhard Zumkeller, Aug 14 2011
(Python)
from sympy import isprime
from itertools import permutations
def a(n): return len(set(t for p in permutations(str(n)) if p[0]!="0" and isprime(t:=int("".join(p)))))
print([a(n) for n in range(1, 106)]) # Michael S. Branicky, Feb 17 2024
CROSSREFS
Sequence in context: A178665 A170958 A178651 * A328515 A356682 A323989
KEYWORD
nonn,easy,base,nice
STATUS
approved