A066205 a(n) = Product_{k=1..n} prime(2k-1), where prime(k) is k-th prime.

2, 10, 110, 1870, 43010, 1333310, 54665710, 2569288370, 151588013830, 10156396926610, 741416975642530, 61537608978329990, 5969148070898009030, 614822251302494930090, 67015625391971947379810, 8510984424780437317235870, 1166004866194919912461314190

Offset

1,1

Comments

Equivalently, a(n) is the product of the first n odd-indexed primes. - Jon E. Schoenfield, Jan 12 2022

Links

Harry J. Smith, Table of n, a(n) for n = 1..100

Example

a(3) = prime(1) * prime(3) * prime(5) = 2 * 5 * 11 = 110.

Maple

a:= proc(n) option remember;
     `if`(n=0, 1, a(n-1)*ithprime(2*n-1))
    end:
seq(a(n), n=1..17);  # Alois P. Heinz, Jan 12 2022

Mathematica

FoldList[Times, Array[Prime[2 # - 1] &, 17]] (* Michael De Vlieger, Jan 12 2022 *)

Prog

(PARI) { for (n=1, 100, p=1; for (k=1, n, p*=prime(2*k - 1)); write("b066205.txt", n, " ", p) ) } \\ Harry J. Smith, Feb 05 2010
(PARI) a(n) = prod(k=1, n, prime(2*k-1)); \\ Michel Marcus, Jan 13 2022

Crossrefs

Cf. A000040, A002110, A066206.

Sequence in context: A212491 A364409 A006608 * A113147 A335946 A206154

Adjacent sequences: A066202 A066203 A066204 * A066206 A066207 A066208

Keyword

nonn

Author

Leroy Quet, Dec 16 2001

Status

approved