A288794 Numbers k such that Lucas(k) + prime(k) is a prime.

1, 6, 12, 18, 54, 75, 354, 10158, 23280, 33726, 38226, 70749, 244779, 308604

Offset: 1

Author

Vincenzo Librandi, Jun 16 2017

Keywords

• nonn
• more

Comments

a(15) > 500000.

Examples

			a(1) = 1 because Lucas(1)=1, prime(1)=2 and 1+2=3 is a prime.
a(2) = 6 because Lucas(6)=18, prime(6)=13 and 18+13=31 is a prime.
		

Crossrefs

Cf. A000032, A000040, A050180.

Programs

Magma

[n: n in [1..950] | IsPrime(Lucas(n)+NthPrime(n))];

Mathematica

Select[Range[1000], PrimeQ[LucasL[#] + Prime[#]] &]

Extensions

a(8)-a(12) from Robert Price, Oct 26 2017

a(13)-a(14) from Robert Price, Dec 16 2017