OFFSET
1,1
LINKS
Vincenzo Librandi and K. D. Bajpai, Table of n, a(n) for n = 1..10000 (first 1000 terms from Vincenzo Librandi)
FORMULA
Sum_{n>=1} 1/a(n) = A242187. - Amiram Eldar, Nov 19 2020
EXAMPLE
From K. D. Bajpai, Aug 27 2014: (Start)
a(2) = 105 is in the sequence because 105 = 3* 5 * 7, product of three successive primes.
a(3) = 385 is in the sequence because 385 = 5 * 7 * 11, product of three successive primes.
(End)
MAPLE
A046301:=n->ithprime(n)*ithprime(n+1)*ithprime(n+2): seq(A028560(n), n=1..100); # K. D. Bajpai, Aug 27 2014
MATHEMATICA
Table[Prime[n] Prime[n+1] Prime[n+2], {n, 50}] (* K. D. Bajpai, Aug 27 2014 *)
Times@@@Partition[Prime[Range[40]], 3, 1] (* Harvey P. Dale, Mar 25 2019 *)
PROG
(Magma) [NthPrime(n)*NthPrime(n+1)*NthPrime(n+2): n in [1..31]]; /* Or: */ [&*[ NthPrime(n+k): k in [0..2] ]: n in [1..31] ]; // Bruno Berselli, Feb 25 2011
(PARI) a(n)=prime(n)*prime(n+1)*prime(n+2); \\ Joerg Arndt, Aug 30 2014
(Haskell)
a046301 n = a046301_list !! (n-1)
a046301_list = zipWith3 (((*) .) . (*))
a000040_list (tail a000040_list) (drop 2 a000040_list)
-- Reinhard Zumkeller, May 12 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Patrick De Geest, Jun 15 1998
EXTENSIONS
Offset changed from 0 to 1 by Vincenzo Librandi, Jan 16 2012
STATUS
approved