A180933 Initial segments of A010051, interpreted as binary numbers, that are prime.

3, 13, 53, 222630977, 3916565571106302349381

Offset

1,1

Comments

The main entry for this sequence is A124077.

The binary expansion of all terms of this sequence is some initial segment of 1101010001010001....

Next terms have 642, 1268, ... decimal digits.

Primes in an initial portion of the infinite binary string built from the prime characteristic function A010051. [From R. J. Mathar, Sep 26 2010]

Links

Table of n, a(n) for n=1..5.

Formula

A000040 INTERSECT A072762. a(n) = A000040(A124077) . [From R. J. Mathar, Sep 26 2010]

Example

a(2) = 13, which is 1101 in binary, corresponding to the characteristic sequence of the primes: 2 is prime, 3 is prime, 4 is composite, 5 is prime.

Maple

Contribution from R. J. Mathar, Sep 26 2010: (Start)
A072762 := proc(n) option remember; if n =1 then return 0; elif n =2 then return 1; end if; if isprime(n) then 2*procname(n-1)+1 ; else 2*procname(n-1) ; end if; end proc:
for n from 1 to 300 do p := A072762(n) ; if isprime(p) then printf("%d, ", p) ; end if; end do: (End)

Prog

(PARI) n=1; for(k=3, 1e4, n+=n+isprime(k); if(isprime(n), print1(n", ")

Crossrefs

Subset of A072762.

Sequence in context: A121240 A065839 A066611 * A048514 A037779 A323264

Adjacent sequences: A180930 A180931 A180932 * A180934 A180935 A180936

Keyword

nonn

Author

Yves Debeuret, Sep 26 2010

Extensions

Extended and rewritten by Charles R Greathouse IV, Sep 27 2010

Status

approved