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A058524 Each c(i) is "multiply" (*) or "divide" (/). a(n) is number of choices for c(1), ..., c(n-1) so that 1 c(1) 2 c(2) 3,.., c(n-1) n is an integer. 3

%I #8 Aug 07 2022 22:10:29

%S 1,1,1,2,2,8,8,13,21,77,77,128,128,354,641,1232,1232,2677,2677,7220,

%T 8951,25378,25378,63680,113335,323151,532358,1442702,1442702,2963955,

%U 2963955,5307221,6739508,21786788,41416560,83691901,83691901,242224403,373640477,669300795,669300795

%N Each c(i) is "multiply" (*) or "divide" (/). a(n) is number of choices for c(1), ..., c(n-1) so that 1 c(1) 2 c(2) 3,.., c(n-1) n is an integer.

%H Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a058/A058524.java">Java program</a> (github)

%F a(p) = a(p-1). - _Sean A. Irvine_, Aug 07 2022

%e For n = 4 there are 2 possibilities: 1*2*3*4=24 and 1/2*3*4=6. For n = 9 there are 13 possibilities: 1*2*3*4*5*6*7*8 1/2*3*4*5*6*7*8 1/2/3*4*5*6*7*8 1*2/3*4*5*6*7*8 1*2*3*4*5/6*7*8 1*2*3/4*5*6*7*8 1*2/3/4*5*6*7*8 1/2*3*4*5/6*7*8 1/2*3/4*5*6*7*8 1/2/3/4*5*6*7*8 1*2*3*4*5*6*7/8 1*2/3*4*5*6*7/8 1*2*3/4*5/6*7*8.

%K nonn,nice

%O 1,4

%A _Naohiro Nomoto_, Dec 22 2000

%E More terms from _Sascha Kurz_, Oct 14 2001

%E a(31)-a(41) from _Sean A. Irvine_, Aug 07 2022

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Last modified April 23 05:37 EDT 2024. Contains 371906 sequences. (Running on oeis4.)