A235646 Primes p such that b=2*p+1 is semiprime, c=2*b+1 is 3-almost prime and d=2*c+1 is 4-almost prime.

43, 1429, 2239, 3319, 4831, 6379, 8821, 10501, 11383, 12781, 13003, 14771, 15091, 16063, 16759, 18223, 19213, 19681, 20021, 22571, 24103, 24109, 24571, 25939, 27271, 28933, 29833, 30241, 31723, 33679, 33811, 34381, 34781, 35591, 35863, 39373

Offset: 1

Author

Zak Seidov, Feb 20 2014

Keywords

• nonn

Examples

			p = 43, b = 87 = 2*29 = A001358(30), c = 175 = 5*5*7 = A014612(43), d = 351 = 3*3*3**13 =  A014613(50).
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Subsequence of A238202.

Cf. A000040, A001358, A014612, A014613, A234095.

Programs

Mathematica

Select[ Prime@ Range@ 4200,PrimeOmega[2#+1]==2 && PrimeOmega[4#+3]==3 && PrimeOmega[8#+7]==4 &] (* Robert G. Wilson v, Feb 22 2014 *)

PARI

forprime(p=43,40000,if(bigomega(a=2*p+1)==2&& bigomega(b=2*c+1)==3&&bigomega(c=2*d+1)==4,print(p",")))