A106066 Primes p such that 1*p+20 and 20*p+1 are primes.

3, 23, 41, 47, 53, 59, 107, 131, 137, 173, 179, 191, 251, 263, 293, 311, 443, 467, 503, 599, 641, 971, 977, 1013, 1049, 1151, 1277, 1301, 1307, 1409, 1427, 1433, 1451, 1559, 1607, 1721, 1913, 1973, 1979, 2069, 2111, 2141, 2267, 2417, 2693, 2729, 2777, 2999

Offset

1,1

Links

Table of n, a(n) for n=1..48.

Mathematica

Select[Prime[Range[220]], PrimeQ[20#+1]&&PrimeQ[1#+20]&]

Prog

(Magma) [p: p in PrimesUpTo(10000)| IsPrime(p+20) and IsPrime(20*p+1)] // Vincenzo Librandi, Nov 13 2010

Crossrefs

Sequence in context: A106892 A370601 A116893 * A281551 A167216 A309935

Adjacent sequences: A106063 A106064 A106065 * A106067 A106068 A106069

Keyword

nonn

Author

Zak Seidov, May 07 2005

Extensions

More terms from Vincenzo Librandi, Apr 01 2010

Status

approved