A072919 a(n) = p(n) - binomial(2n,n), where p(n) is the least prime greater than binomial(2n,n).

1, 1, 3, 1, 5, 5, 1, 19, 3, 21, 5, 1, 3, 7, 31, 43, 61, 17, 1, 101, 59, 1, 11, 11, 5, 13, 57, 73, 73, 39, 65, 127, 73, 29, 121, 97, 51, 1, 51, 9, 191, 227, 37, 107, 109, 1, 223, 317, 23, 37, 35, 185, 139, 13, 5, 55, 65, 19, 121, 313, 61, 1, 227, 43, 223, 91, 197, 1, 151, 7, 23

Offset

1,3

Links

Table of n, a(n) for n=1..71.

Mathematica

a[n_] := Module[{r, p}, p = Binomial[2n, n]; r = p + 1; While[ ! PrimeQ[r], r = r + 1]; r - p]; Table[a[i], {i, 1, 100}]
NextPrime[#]-#&/@Table[Binomial[2n, n], {n, 80}] (* Harvey P. Dale, Jan 11 2025 *)

Crossrefs

Sequence in context: A344725 A209560 A211977 * A273171 A244420 A378999

Adjacent sequences: A072916 A072917 A072918 * A072920 A072921 A072922

Keyword

easy,nonn

Author

Joseph L. Pe, Aug 11 2002

Status

approved