A075872 a(n) = binomial(prime(n),n)/prime(n) where prime(n) = n-th prime.

1, 1, 2, 5, 42, 132, 1144, 3978, 35530, 690690, 2731365, 50067108, 429757960, 1822766520, 15991836267, 280086337895, 4703540164785, 21512315482350, 360471372561300, 3174207914954076, 14859478810664136, 248599618581498860, 2209822117125283440, 36246606227404101045

Offset

1,3

Comments

A prime p divides all the entries (binomial coefficients) in the p-th row of Pascal's triangle.

Links

Table of n, a(n) for n=1..24.

Formula

a(n) = A060604(n)/A000040(n).

Maple

seq(binomial(ithprime(n), n)/ithprime(n), n=1..30);

Mathematica

f[n_]:=Module[{pn=Prime[n]}, Binomial[pn, n]/pn]
f/@Range[30]  (* Harvey P. Dale, Feb 25 2011 *)

Prog

(PARI) a(n) = my(p=prime(n)); binomial(p, n)/p; \\ Michel Marcus, Jul 15 2022

Crossrefs

Cf. A060604, A000040.

Sequence in context: A093625 A042447 A176266 * A075891 A246669 A208302

Adjacent sequences: A075869 A075870 A075871 * A075873 A075874 A075875

Keyword

nonn

Author

Lekraj Beedassy, Oct 16 2002

Extensions

More terms from Emeric Deutsch, Mar 04 2004

Status

approved