A261726 a(n) = binomial(prime(n+1)-1, prime(n)-1).

2, 6, 15, 210, 66, 1820, 153, 7315, 376740, 435, 1947792, 91390, 861, 163185, 20358520, 40475358, 1770, 90858768, 916895, 2556, 256851595, 1749060, 541931236, 132601016340, 3921225, 5151, 4967690, 5778, 6210820, 1378095785451705375, 11358880, 7858539612

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

a(n) = binomial(prime(n+1)-1, prime(n)-1).

Example

For n = 2, a(n) = binomial(prime(n+1)-1, prime(n)-1) = binomial(4,2) = 6.

Mathematica

Binomial[#[[2]]-1, #[[1]]-1]&/@Partition[Prime[Range[40]], 2, 1] (* Harvey P. Dale, Apr 01 2021 *)

Prog

(PARI) a(n) = binomial(prime(n+1)-1, prime(n)-1);
vector(35, n, a(n))

Crossrefs

Cf. A000040, A001700, A104861.

Sequence in context: A356803 A375522 A376051 * A302775 A181993 A123475

Adjacent sequences: A261723 A261724 A261725 * A261727 A261728 A261729

Keyword

nonn,easy

Author

Altug Alkan, Sep 14 2015

Status

approved