A375337 - OEIS

A375337

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

1, 3, 10, 35, 330, 1716, 12376, 75582, 490314, 4292145, 300540195, 17672631900, 7898654920, 960566918220, 1503232609098, 64617565719070, 109712808959985, 232714176627630544, 13413576695470557606, 5300174441392685400, 873065282167813104916, 13146145590943010676030

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

This sequence is a pseudo-random subsequence of Pascal's triangle.

LINKS

Table of n, a(n) for n=1..22.

FORMULA

a(n) << 2^p/sqrt(p), where p = prime(n). - Charles R Greathouse IV, Aug 12 2024

EXAMPLE

a(4) = 35 because binomial(prime(4), phi(prime(4) + 1)) = binomial(7, phi(8)) = binomial(7, 4) = 35.

MATHEMATICA