A056615 Binomial(2*n - 1, n - 1) - 1 (mod n^2).

0, 2, 0, 2, 0, 29, 0, 34, 9, 77, 0, 61, 0, 51, 134, 34, 0, 137, 0, 9, 401, 123, 0, 269, 125, 171, 252, 475, 0, 811, 0, 290, 977, 869, 615, 673, 0, 363, 9, 409, 0, 755, 0, 1123, 1259, 531, 0, 1421, 1715, 1127, 2321, 1555, 0, 1919, 1940, 2171, 1814, 843, 0, 3527, 0, 963

Offset

1,2

Comments

Binomial(2*n - 1, n - 1] - 1 (mod n^2) = 0 iff n is an odd prime.

Links

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

Mathematica

Table[Mod[Binomial[2*n - 1, n - 1] - 1, n^2], {n, 1, 100}]

Crossrefs

Sequence in context: A137949 A019214 A137668 * A060989 A135298 A006996

Adjacent sequences: A056612 A056613 A056614 * A056616 A056617 A056618

Keyword

nonn

Author

Robert G. Wilson v, Aug 07 2000

Status

approved