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

1,1

Comments

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

Links

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

Example

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

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);

Prog

(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

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

Sequence in context: A045238 A139982 A171252 * A180549 A247436 A063351

Adjacent sequences: A119484 A119485 A119486 * A119488 A119489 A119490

Keyword

easy,nonn

Author

Paolo P. Lava and Giorgio Balzarotti, May 23 2006

Status

approved