A205150 s(k)-s(j), where (s(k),s(j)) is the least such pair for which n divides their difference, and s(j)=prime(j)*prime(j+1).

9, 20, 9, 20, 20, 42, 42, 128, 9, 20, 66, 108, 78, 42, 180, 128, 102, 108, 114, 20, 42, 66, 230, 144, 850, 78, 108, 308, 29, 180, 62, 128, 66, 102, 2485, 108, 370, 114, 78, 360, 246, 42, 215, 308, 180, 230, 893, 144, 294, 850, 102, 884, 636, 108, 1980

Offset: 1

Author

Clark Kimberling, Jan 25 2012

Keywords

• nonn

Comments

For a guide to related sequences, see A204892.

Links

• Michel Marcus, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A205146, A204892.

Programs

Mathematica

(See the program at A205146.)

PARI

s(m) = prime(m)*prime(m+1);
isok(k, n) = my(sk=s(k)); for (j=1, k-1, if (!Mod(sk-s(j), n), return (j)));
a(n) = my(k=1, x); while (!(j=isok(k, n)), k++); s(k) - s(j); \\ Michel Marcus, Jul 23 2021