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A246663 Products of swinging factorials A056040. 1
1, 2, 4, 6, 8, 12, 16, 20, 24, 30, 32, 36, 40, 48, 60, 64, 70, 72, 80, 96, 120, 128, 140, 144, 160, 180, 192, 216, 240, 252, 256, 280, 288, 320, 360, 384, 400, 420, 432, 480, 504, 512, 560, 576, 600, 630, 640, 720, 768, 800, 840, 864, 900, 960, 1008, 1024 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..56.

MATHEMATICA

sw[n_] := n!/(Floor[n/2]!)^2; lim = 40; For[p = 0; a = f = Table[sw[n], {n, lim}], p =!= a, p = a; a = Select[Union@@Outer[Times, f, a], #<= sw[lim]&]]; a (* Hans Havermann, Sep 09 2014 *)

PROG

(Sage)

# For example prod_hull(A008578) are the natural numbers.

def prod_hull(f, K):

    S = []; newS = []

    n = 0

    while f(n) <= K:

        newS.append(f(n))

        n += 1

    while newS <> S:

        S = newS; T = []

        for s in S:

            M = map(lambda n: n*s , S)

            T.extend(filter(lambda n: n <= K, M))

        newS = Set(T).union(Set(S))

    return sorted(newS)

prod_hull(lambda n: factorial(n)/factorial(n//2)^2, 1024)

CROSSREFS

Cf. A001013 is a sublist.

Sequence in context: A219653 A050622 A082662 * A182568 A064522 A036912

Adjacent sequences:  A246660 A246661 A246662 * A246664 A246665 A246666

KEYWORD

nonn,easy

AUTHOR

Peter Luschny, Sep 09 2014

STATUS

approved

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Last modified September 18 12:00 EDT 2019. Contains 327170 sequences. (Running on oeis4.)