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A304102 a(n) = Product_{d|n, d<n} prime(A304101(d)-1). 7
1, 2, 2, 4, 2, 8, 2, 12, 4, 8, 2, 120, 2, 12, 8, 24, 2, 200, 2, 120, 12, 12, 2, 1680, 4, 8, 20, 180, 2, 2000, 2, 120, 12, 44, 12, 12600, 2, 44, 8, 1680, 2, 1200, 2, 180, 200, 20, 2, 42000, 6, 440, 44, 120, 2, 7800, 12, 3960, 44, 12, 2, 3234000, 2, 44, 120, 840, 8, 10200, 2, 264, 20, 3000, 2, 630000, 2, 20, 440, 1452, 18, 2000, 2, 109200, 260, 44, 2, 1386000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..4181

FORMULA

a(n) = Product_{d|n, d<n} A000040(A304101(d)-1).

a(n) = 2*A304104(n) / A000040(A304101(n)-1).

Other identities. For all n >= 1:

A001222(a(n)) = A032741(n).

A007814(a(n)) = A293435(n).

A007949(a(n)) = A304095(n).

PROG

(PARI)

\\ Needs also code from A304101:

A304102(n) = { my(m=1); fordiv(n, d, if(d<n, m *= prime(A304101(d)-1))); (m); };

CROSSREFS

Cf. A304101, A304103 (restricted growth sequence transform of this sequence), A304104.

Sequence in context: A157019 A067538 A305982 * A096154 A270365 A200147

Adjacent sequences:  A304099 A304100 A304101 * A304103 A304104 A304105

KEYWORD

nonn

AUTHOR

Antti Karttunen, May 13 2018

STATUS

approved

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Last modified June 15 20:50 EDT 2019. Contains 324145 sequences. (Running on oeis4.)