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A129108 a(0)=1; a(n) is the smallest positive integer such that lcm(a(n-1), a(n)) = n!. 1
1, 1, 2, 3, 8, 15, 144, 35, 1152, 2835, 6400, 6237, 6220800, 1001, 609638400, 13030875, 1605632, 221524875, 21069103104, 5773625, 52672757760000, 311834363841, 39649280000, 652017306213, 18730002677760000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Charlie Neder, Table of n, a(n) for n = 0..619

FORMULA

If n! = Product p_i^e_i, then a(n) = Product{p_i^e_i : n has even remainder mod p_i}. - Charlie Neder, Jan 06 2019

EXAMPLE

lcm(a(5), a(6)) = lcm(15, 144) = 720 = 6!.

MAPLE

A129108 := proc(nmax) local a, x, i, n, anext; a :=[1] ; while nops(a) < nmax do n := nops(a) : x :=sort([op(numtheory[divisors](n!))]) : for i from 1 to nops(x) do anext := op(i, x) ; if lcm(op(-1, a), anext) = factorial(n) then break ; fi ; od ; a := [op(a), anext] ; od ; a ; end: A129108(25) ; # R. J. Mathar, Jun 15 2007; corrected by Paolo P. Lava, Jan 07 2019

CROSSREFS

Sequence in context: A148013 A133983 A005162 * A230284 A264235 A160622

Adjacent sequences:  A129105 A129106 A129107 * A129109 A129110 A129111

KEYWORD

nonn

AUTHOR

Leroy Quet, May 24 2007

EXTENSIONS

More terms from R. J. Mathar, Jun 15 2007

a(14)-a(24) corrected by Charlie Neder, Jan 06 2019

STATUS

approved

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Last modified December 2 17:52 EST 2020. Contains 338880 sequences. (Running on oeis4.)