A369059 a(0) = 0, and for n > 0, a(n) is the square of the product of first n-1 odd primes.

0, 1, 9, 225, 11025, 1334025, 225450225, 65155115025, 23520996524025, 12442607161209225, 10464232622576958225, 10056127550296456854225, 13766838616355849433434025, 23142055714094182897602596025, 42789661015360144177667200050225, 94522361182930558488466844910947025, 265513312562851938794103367354850193225

Offset

0,3

Comments

Terms a(2) .. a(9) are equal to the terms A360435(1..8).

Links

Table of n, a(n) for n=0..16.

Index entries for sequences related to primorial numbers

Formula

a(n) = A002620(A002110(n)).

For n > 0, a(n) = A061742(n)/4 = A070826(n)^2.

For n > 0, a(n) >= A368704(n) and for n > 1, a(n) >= A360435(n-1).

For n > 0, A000005(a(n)) = A000244(n-1) = 3^(n-1).

Mathematica

Join[{0}, FoldList[Times, 1, Prime[Range[2, 16]]^2]] (* Amiram Eldar, Jan 19 2024 *)

Prog

(PARI)
A002110(n) = prod(i=1, n, prime(i));
A002620(n) = ((n^2)>>2);
A369059(n) = A002620(A002110(n));

Crossrefs

Cf. A000005, A000244, A002110, A002620, A061742, A070826, A360435.

An upper bound for A368704, and also for A360435(n-1).

Sequence in context: A294971 A001818 A360435 * A095363 A138564 A285985

Adjacent sequences: A369056 A369057 A369058 * A369060 A369061 A369062

Keyword

nonn

Author

Antti Karttunen, Jan 19 2024

Status

approved