

A129108


a(0)=1; a(n) is the smallest positive integer such that lcm(a(n1), 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
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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



