A214936 a(0) = 1, a(n) = a(n - 1) * (length of binary representation of n).

1, 1, 2, 4, 12, 36, 108, 324, 1296, 5184, 20736, 82944, 331776, 1327104, 5308416, 21233664, 106168320, 530841600, 2654208000, 13271040000, 66355200000, 331776000000, 1658880000000, 8294400000000, 41472000000000, 207360000000000, 1036800000000000, 5184000000000000

Offset

0,3

Links

Table of n, a(n) for n=0..27.

Formula

a(0) = 1, for n > 0: a(n) = a(n - 1) * (Length of binary representation of n) = a(n - 1) * A070939(n).

Example

a(4) = 12 because a(3) = 4 and 4 in binary is 100 (3 bits), and thus 4 * 3 = 12.

Mathematica

nxt[{n_, a_}]:={n+1, a*IntegerLength[n+1, 2]}; Transpose[NestList[nxt, {0, 1}, 30]][[2]] (* Harvey P. Dale, Oct 11 2015 *)

Prog

(Python)
t = 1
for n in range(1, 33):
    print t,
    t *= len(bin(n))-2

Crossrefs

Cf. A070939.

Cf. A083652: a(0)=1, for n>0: a(n)=a(n-1)+A070939(n).

Sequence in context: A149840 A224540 A025579 * A010552 A149841 A149842

Adjacent sequences: A214933 A214934 A214935 * A214937 A214938 A214939

Keyword

nonn,base,easy

Author

Alex Ratushnyak, Jul 29 2012

Status

approved