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A109490 Value of Product[k/sd(k,3),k=1..n], where sd[k,b] is the sum of the digits of k represented in base b. 2

%I #8 Jan 22 2018 03:05:56

%S 1,1,3,6,10,30,70,140,1260,6300,23100,138600,600600,2102100,10510500,

%T 42042000,142942800,1286485200,8147739600,40738698000,285170886000,

%U 1568439873000,7214823415800,43288940494800,216444702474000

%N Value of Product[k/sd(k,3),k=1..n], where sd[k,b] is the sum of the digits of k represented in base b.

%C See A109489 for the corresponding base-2 sequence.

%C For n=601 the sum is not an integer (its denominator is 7). B-file contains all terms before that.

%H Robert Israel, <a href="/A109490/b109490.txt">Table of n, a(n) for n = 1..600</a>

%p P:= 1: A[1]:= P:

%p for n from 2 to 100 do

%p P:= P*n/convert(convert(n,base,3),`+`);

%p A[n]:= P;

%p od:

%p seq(A[i],i=1..100); # _Robert Israel_, Jan 21 2018

%Y Cf. A109489.

%K nonn,base,easy,fini

%O 1,3

%A _John W. Layman_, Jun 29 2005

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Last modified March 29 01:34 EDT 2024. Contains 371264 sequences. (Running on oeis4.)