A067548 Least k > n such that gcd(prime(n)+k, n+prime(k)) > 1.

2, 6, 5, 5, 7, 17, 9, 11, 11, 13, 13, 23, 15, 26, 17, 17, 19, 19, 20, 22, 22, 23, 25, 26, 26, 29, 29, 33, 31, 41, 32, 34, 35, 35, 37, 54, 38, 44, 41, 43, 43, 44, 45, 47, 47, 53, 49, 96, 51, 53, 52, 55, 55, 64, 57, 57, 59, 59, 61, 91, 62, 67

Offset

1,1

Links

Table of n, a(n) for n=1..62.

Example

a(2)=6 as: gcd(prime(2)+6,2+prime(6)) = gcd(3+6,2+13) = gcd(9,15) = 3 and gcd(prime(2)+k,2+prime(k))=1 for 2<k<6.

Prog

(PARI) a(n) = my(k=n+1); while(gcd(prime(n)+k, n+prime(k)) == 1, k++); k; \\ Michel Marcus, Feb 05 2021

Crossrefs

Sequence in context: A316134 A273621 A190124 * A354509 A245698 A053793

Adjacent sequences: A067545 A067546 A067547 * A067549 A067550 A067551

Keyword

nonn

Author

Reinhard Zumkeller, Jan 28 2002

Status

approved