A305982 a(n) = Product_{d|n, d<n} prime(A305793(1+d)-1), where A305973(k) records the prime signature of 2k-1.

1, 2, 2, 4, 2, 8, 2, 12, 4, 8, 2, 48, 2, 20, 8, 24, 2, 32, 2, 120, 20, 8, 2, 288, 4, 28, 8, 120, 2, 320, 2, 120, 8, 20, 20, 576, 2, 20, 28, 480, 2, 320, 2, 264, 32, 8, 2, 4320, 10, 200, 20, 168, 2, 320, 8, 1200, 20, 8, 2, 11520, 2, 44, 80, 600, 28, 704, 2, 300, 8, 800, 2, 6912, 2, 44, 80, 300, 20, 448, 2, 31200, 40, 8, 2, 72000, 20, 20, 8

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..8192

Formula

a(n) = Product_{d|n, d<n} A008578(A305793(1+d)).

Prog

(PARI) A305982(n) = { my(m=1); fordiv(n, d, if((d<n), m *= prime(A305973(1+d)-1))); (m); }; \\ Needs also code from A305973.

Crossrefs

Cf. A305973, A305983 (rgs-transform), A305984.

Sequence in context: A157019 A359906 A067538 * A304102 A096154 A270365

Adjacent sequences: A305979 A305980 A305981 * A305983 A305984 A305985

Keyword

nonn

Author

Antti Karttunen, Jun 15 2018

Status

approved