A271512 a(n) = (p+1)*(p+2)*(p+3)/6 where p is the n-th prime.

10, 20, 56, 120, 364, 560, 1140, 1540, 2600, 4960, 5984, 9880, 13244, 15180, 19600, 27720, 37820, 41664, 54740, 64824, 70300, 88560, 102340, 125580, 161700, 182104, 192920, 215820, 227920, 253460, 357760, 392084, 447580, 467180, 573800, 596904, 669920, 748660

Offset: 1

Author

Vincenzo Librandi, Apr 10 2016

Keywords

• nonn
• easy

Comments

Subsequence of A000292.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040, A000292, A271511.

Programs

Magma

[(p+1)*(p+2)*(p+3) / 6: p in PrimesUpTo(200)];

Maple

A271512:=n->(ithprime(n)+1)*(ithprime(n)+2)*(ithprime(n)+3)/6: seq(A271512(n), n=1..80); # Wesley Ivan Hurt, Apr 10 2016

Mathematica

Table[(Prime[n]^3 + 6 Prime[n]^2 + 11 Prime[n] + 6) / 6, {n, 50}]

PARI

lista(nn) = forprime(p=2, nn, print1((p+1)*(p+2)*(p+3)/6, ", ")); \\ Altug Alkan, Apr 10 2016

Python

from sympy import prime
for n in range(1,1000):
    p=prime(n)
    print((int)(((p+1)*(p+2)*(p+3))/6))
# Soumil Mandal, Apr 11 2016

Formula

a(n) = A000292(A000040(n)+1). - Michel Marcus, Apr 10 2016