

A227795


For each base, b, beginning with binary, the number of (b1)digit primes with one copy of each digit save one.


0



0, 3, 1, 9, 52, 283, 2113, 16142, 145227, 1359133, 15000161, 172888810, 2217146126
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OFFSET

2,2


COMMENTS

Note that only decimal 2, 11 and 19 are representable in some base using a copy of each digit in that base (base 2 for the first and base 3 for the others), as a number written in base b with a single copy of each digit is congruent to either 0 or (b1)/2 modulo b1.


LINKS

Table of n, a(n) for n=2..14.


EXAMPLE

In base 3, 10, 12 and 21 are primes: Decimal 3, 5 and 7. In base 4, of the possibilities only 103 is prime: Decimal 19.


PROG

(PARI) \\ Starts at base 4 and prints in form 'base:count', bases 2 and 3 done by hand.
{
b=4; while(1,
c=0; for(i=1, b!, perm=numtoperm(b, i);
if(perm[b1]!=1,
if(gcd(b, perm[1]1)==1,
if(gcd(b1, perm[b]1)==1,
n=sum(j=1, b1, (perm[j]1)*b^(j1));
if(ispseudoprime(n), c++)))));
print1(b":"c"\n"); b++)
}


CROSSREFS

Cf. A073643, A116670.
Sequence in context: A105951 A038202 A128415 * A090479 A227758 A304638
Adjacent sequences: A227792 A227793 A227794 * A227796 A227797 A227798


KEYWORD

nonn,base,less


AUTHOR

James G. Merickel, Sep 23 2013


EXTENSIONS

a(14) added by James G. Merickel, Oct 14 2013


STATUS

approved



