A007876 a(2n-1) = n*a(2n-2), a(2n) = n*a(2n-1) + 1.

1, 2, 4, 9, 27, 82, 328, 1313, 6565, 32826, 196956, 1181737, 8272159, 57905114, 463240912, 3705927297, 33353345673, 300180111058, 3001801110580, 30018011105801, 330198122163811, 3632179343801922, 43586152125623064

Offset

1,2

Links

Table of n, a(n) for n=1..23.

Crossrefs

Sequence in context: A110138 A148085 A003320 * A343845 A349404 A332979

Adjacent sequences: A007873 A007874 A007875 * A007877 A007878 A007879

Keyword

nonn,easy

Author

buzzard(AT)math.berkeley.edu (Kevin Buzzard)

Status

approved