

A109897


Group the natural numbers so that every 2nth group product is divisible by the single number in the next group. (1), (2,3,4,5), (6), (7,8,9,10,11), (12), (13,14,15,16,17,18,19),(20), (21,22,23,24,25,26,27),(28),... Sequence contains the product of terms in the 2nth group.


3



120, 55440, 253955520, 4475671200, 33891580800, 7146019520640, 106137499051584000, 240679032790296606105600, 74684882115043200, 230656425830328960, 66654064122818055916032000, 171176782669200, 282328002094320, 126639913316232476160000, 859891329773280
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OFFSET

1,1


LINKS

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


EXAMPLE

a(2) = 7*8*9*10*11 = 55440.


PROG

(PARI) m=1; for(k=2, 150, if(m%k==0, print1(m", "); m=1, m*=k))


CROSSREFS

Cf. A079759, A109895, A109896.
Sequence in context: A146550 A006176 A275455 * A301393 A074653 A065961
Adjacent sequences: A109894 A109895 A109896 * A109898 A109899 A109900


KEYWORD

nonn


AUTHOR

Amarnath Murthy, Jul 13 2005


EXTENSIONS

Terms from a(5) from Franklin T. AdamsWatters, Jun 26 2011


STATUS

approved



