OFFSET
1,1
COMMENTS
There are 18 digit pairs which can produce such primes: (1,0),(1,3),(1,4),(1,6),(1,7),(1,9),(2,3),(2,9),(3,4),(3,5),(3,7),(3,8),(4,7),(4,9),(5,9),(6,7),(7,9),(8,9).
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..18167 (first 1000 terms from T. D. Noe)
MATHEMATICA
Select[FromDigits/@Tuples[{0, 1}, 14], PrimeQ[#] && Length[x=IntegerDigits[#]]==2*Count[x, 0] &] (* Jayanta Basu, May 23 2013 *)
PROG
(PARI) \\ B(k, d1, d2, pred) k-digits of (d1, d2) each, satisfying pred.
B(k, d1, d2, pred)={my(L=List(), m=10^(2*k-1)); forsubset([2*k, k], s, my(t=(10^(2*k)-1)/9*d1 + (d2-d1)*sum(i=1, #s, 10^(s[i]-1))); if(t>=m && pred(t), listput(L, t))); vecsort(Vec(L))}
{ concat(vector(7, k, B(k, 0, 1, isprime)))[1..20] } \\ Andrew Howroyd, Sep 20 2024
CROSSREFS
Primes in A071925.
The 18 sequences in this family are: this sequence (1,0), A087511 (1,3), A087512 (1,4), A087513 (1,6), A087514 (1,7), A087515 (1,9), A087527 (2,3), A087528 (2,9), A087529 (3,4), A087530 (3,5), A087531 (3,7), A087532 (3,8), A087533 (4,7), A087534 (4,9), A087535 (5,9), A087536 (6,7), A087537 (7,9), A087538 (8,9).
KEYWORD
base,nonn
AUTHOR
Paul D. Hanna and Amarnath Murthy, Sep 11 2003
STATUS
approved