A119487 Primes of the form i*prime(i) + (i+1)*prime(i+1).

43, 83, 197, 271, 359, 631, 977, 1307, 1553, 2371, 2693, 2953, 3271, 4561, 5051, 5407, 6551, 8713, 9941, 10651, 22573, 23333, 27689, 31051, 33203, 34123, 37507, 52639, 60919, 64399, 79279, 82699, 93559, 112061, 119131, 136033, 146921, 197959

Offset: 1

Author

Paolo P. Lava and Giorgio Balzarotti, May 23 2006

Keywords

• easy
• nonn

Comments

Primes in A152117; also called linking primes, cf. A152658. - Klaus Brockhaus, Dec 11 2008

Examples

			The third prime is 5 and the fourth is 7. Therefore 5*3 + 7*4 = 15 + 28 = 43 which is a prime.
		

Links

• Klaus Brockhaus, Table of n, a(n) for n=1..10000

Crossrefs

Cf. A119488.

Cf. A152117 (n*(n-th prime) + (n+1)*((n+1)-th prime)), A152658 (beginnings of maximal chains of primes). - Klaus Brockhaus, Dec 11 2008

Programs

Magma

[ q: n in [1..133] | IsPrime(q) where q is n*p+(n+1)*NextPrime(p) where p is NthPrime(n) ] // Klaus Brockhaus, Dec 11 2008

Maple

P:=proc(n) local i,j; for i from 1 by 1 to n do j:=ithprime(i)*i +ithprime(i+1)*(i+1); if isprime(j) then print(i); fi; od; end: P(200);