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A269694 Product of first n nonzero Jacobsthal numbers (A001045). 1
1, 1, 3, 15, 165, 3465, 148995, 12664575, 2165642325, 738484032825, 504384594419475, 688484971382583375, 1880252456845835197125, 10268058666835106011499625, 112158004817839862963610403875 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Inspired by A015013.

LINKS

Table of n, a(n) for n=1..15.

FORMULA

a(n) = abs(A015013(n)).

EXAMPLE

a(4) = 15 because a(4) = 1*1*3*5 = 15.

MATHEMATICA

Table[Abs@QFactorial[n, -2], {n, 20}] (* Vladimir Reshetnikov, Sep 16 2016 *)

FoldList[Times, LinearRecurrence[{1, 2}, {1, 1}, 20]] (* Harvey P. Dale, Apr 22 2019 *)

PROG

(PARI) a001045(n) = (2^n - (-1)^n) / 3;

a(n) = prod(i=1, n, a001045(i));

CROSSREFS

Cf. A001045, A015013.

Sequence in context: A097489 A080696 A015013 * A153280 A132683 A059386

Adjacent sequences:  A269691 A269692 A269693 * A269695 A269696 A269697

KEYWORD

nonn,easy

AUTHOR

Altug Alkan, Apr 05 2016

STATUS

approved

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Last modified February 21 02:02 EST 2020. Contains 332086 sequences. (Running on oeis4.)