A066752 a(n) = gcd(prime(n)+1, n+1).

1, 1, 2, 1, 6, 7, 2, 1, 2, 1, 4, 1, 14, 1, 16, 1, 6, 1, 4, 3, 2, 1, 12, 5, 2, 3, 4, 1, 10, 1, 32, 33, 2, 35, 6, 1, 2, 1, 8, 1, 6, 1, 4, 1, 2, 1, 4, 7, 2, 1, 26, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 21, 4, 13, 2, 1, 4, 1, 2, 1, 6, 1, 2, 1, 76, 1, 78, 1, 2, 1, 2, 1, 12, 1, 2, 3, 2, 1, 6, 1, 4, 3, 2, 1, 4, 1, 2, 9, 4

Offset

1,3

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Example

a(23) = gcd(prime(23)+1,23+1) = gcd(83+1,24) = gcd(84,24) = 12*gcd(7,2) = 12.

Mathematica

Table[GCD[Prime[w]+1, w+1], {w, 1, 128}]

Prog

(PARI) { for (n=1, 1000, write("b066752.txt", n, " ", gcd(prime(n) + 1, n + 1)) ) } \\ Harry J. Smith, Mar 22 2010

Crossrefs

Cf. A000040.

Cf. A084309-A084316.

Sequence in context: A172430 A325139 A084312 * A192329 A059364 A258870

Adjacent sequences: A066749 A066750 A066751 * A066753 A066754 A066755

Keyword

nonn

Author

Reinhard Zumkeller, Jan 16 2002

Extensions

More terms from Labos Elemer, Jun 13 2003

Status

approved