A332030 a(n) is the product of the distinct positive numbers whose binary digits appear in order, but not necessarily as consecutive digits, in the binary representation of n.
1, 1, 2, 3, 8, 30, 36, 21, 64, 1080, 7200, 2310, 1728, 16380, 3528, 315, 1024, 146880, 9331200, 1580040, 13824000, 1362160800, 170755200, 796950, 331776, 176904000, 2861913600, 72972900, 4741632, 99754200, 1587600, 9765, 32768, 77552640, 86294937600
Offset: 0
Examples
For n = 9: - the binary representation of 9 is "1001", - the following positive binary strings appear in it: "1", "10", "11", "100", "101" and "1001", - they correspond to: 1, 2, 3, 4, 5 and 9, - so a(9) = 1 * 2 * 3 * 4 * 5 * 9 = 1080.
Links
- Rémy Sigrist, Table of n, a(n) for n = 0..4096
Programs
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PARI
a(n) = my (b=binary(n), s=[0]); for (i=1, #b, s=setunion(s, apply(m -> 2*m+b[i], s))); vecprod(s[2..#s])
Comments