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.

1, 1, 1, 2, 2, 8, 8, 13, 21, 77, 77, 128, 128, 354, 641, 1232, 1232, 2677, 2677, 7220, 8951, 25378, 25378, 63680, 113335, 323151, 532358, 1442702, 1442702, 2963955, 2963955, 5307221, 6739508, 21786788, 41416560, 83691901, 83691901, 242224403, 373640477, 669300795, 669300795

Offset: 1

Author

Naohiro Nomoto, Dec 22 2000

Keywords

• nonn
• nice

Examples

			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.
		

Links

• Sean A. Irvine, Java program (github)

Formula

a(p) = a(p-1). - Sean A. Irvine, Aug 07 2022

Extensions

More terms from Sascha Kurz, Oct 14 2001

a(31)-a(41) from Sean A. Irvine, Aug 07 2022