A127920 1/6 of product of three numbers: n-th prime, previous and following number.

1, 4, 20, 56, 220, 364, 816, 1140, 2024, 4060, 4960, 8436, 11480, 13244, 17296, 24804, 34220, 37820, 50116, 59640, 64824, 82160, 95284, 117480, 152096, 171700, 182104, 204156, 215820, 240464, 341376, 374660, 428536, 447580, 551300, 573800, 644956

Offset

1,2

Links

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

Formula

a(n) = A127918(n)/3. - Michel Marcus, Apr 09 2017

Mathematica

Table[(Prime[n] + 1) Prime[n](Prime[n] - 1)/6, {n, 1, 100}]
((#-1)#(#+1))/6&/@Prime[Range[40]] (* Harvey P. Dale, Dec 23 2019 *)

Prog

(PARI) forprime(p=2, 1e3, print1(binomial(p+1, 3)", ")) \\ Charles R Greathouse IV, Jun 16 2011
(Python)
from sympy import prime
print([(prime(n) - 1)*prime(n)*(prime(n) + 1)//6 for n in range(1, 101)]) # Indranil Ghosh, Apr 09 2017
(Magma) [(NthPrime(n) + 1)*NthPrime(n)*(NthPrime(n) - 1)/6: n in [1..40]]; // Vincenzo Librandi, Apr 09 2017

Crossrefs

Cf. A036689, A034953, A127917, A127918, A127919.

Sequence in context: A047810 A002492 A358927 * A060122 A066970 A196295

Adjacent sequences: A127917 A127918 A127919 * A127921 A127922 A127923

Keyword

nonn,easy

Author

Artur Jasinski, Feb 06 2007

Status

approved