OFFSET

1,1

COMMENTS

Variation on Schinzel's Hypothesis.

LINKS

Paolo P. Lava, Table of n, a(n) for n = 1..1000

Eric Weisstein's World of Mathematics, Schinzel's Hypothesis.

EXAMPLE

For n=1 the minimum primes p and q are 3 and 5: (p+1)/(q-1) = (3+1)/(5-1) = 4/4 = 1. Therefore a(1)=3.

For n=2 the minimum primes p and q are 3 and 3: (p+1)/(q-1) = (3+1)/(3-1) = 4/2 = 2. Therefore a(2)=3.

MAPLE

with(numtheory): P:=proc(q) local k, n;

for n from 1 to q do for k from 1 to q do

if isprime(n*(ithprime(k)-1)-1) then print(n*(ithprime(k)-1)-1);

break; fi; od; od; end: P(10^5);

PROG

(PARI) a(n) = my(q=2); while(! isprime(p=n*(q-1)-1), q = nextprime(q+1)); p; \\ Michel Marcus, Nov 07 2014

CROSSREFS

KEYWORD

nonn,easy

AUTHOR

Paolo P. Lava, Nov 06 2014

STATUS

approved