A183059 Cyclops primes p such that 2p+1 is also a Cyclops prime.

12011, 12041, 13049, 18041, 21011, 22013, 28019, 29021, 29033, 31019, 33023, 37013, 37049, 38039, 42023, 43013, 48029, 1110269, 1120349, 1120481, 1130273, 1130429, 1140143, 1140311, 1140341, 1140383, 1140413, 1140449, 1160129, 1160213, 1160429, 1170173, 1170329, 1170443

Offset

1,1

Comments

Primes p such that both p and 2p+1 are Cyclops primes A134809.

By definition all terms are also Sophie Germain primes A005384.

Links

Table of n, a(n) for n=1..34.

Example

a(1) = 12011 is in the sequence because 12011 is a Cyclops prime A134809 and 2*12011+1 = 24023 is also a Cyclops prime.

Maple

isA134808 := proc(n) local dgs, ndgs; dgs := convert(n, base, 10) ; mdg := (nops(dgs)+1)/2 ; if type(nops(dgs), 'even') then false; elif n = 0 then true; else if op(mdg, dgs) <> 0 then false; else if mul(op(k, dgs), k=1..mdg-1) =0 or mul(op(k, dgs), k=mdg+1..nops(dgs)) = 0 then false; else true; end if; end if; end if; end proc:
isA134809 := proc(n) isprime(n) and isA134808(n) ; end proc:
isA183059 := proc(n) isA134809(n) and isA134809(2*n+1) ; end proc:
for n from 0 to 1200000 do if isA183059(n) then printf("%d, ", n); end if; end do: # R. J. Mathar, Jan 05 2011

Crossrefs

Cf. A005384, A134808, A134809, A183058.

Sequence in context: A251163 A236607 A156713 * A287046 A235308 A064966

Adjacent sequences: A183056 A183057 A183058 * A183060 A183061 A183062

Keyword

nonn,base,less

Author

Omar E. Pol, Dec 25 2010

Status

approved