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A075159 Run lengths in the binary expansion of n-1 gives the vector of exponents in prime factorization of a(n), with the least significant run corresponding to the exponent of the least prime, 2. 6
1, 2, 3, 4, 6, 5, 9, 8, 12, 15, 7, 10, 18, 25, 27, 16, 24, 45, 35, 30, 14, 11, 21, 20, 36, 75, 49, 50, 54, 125, 81, 32, 48, 135, 175, 90, 70, 77, 105, 60, 28, 33, 13, 22, 42, 55, 63, 40, 72, 225, 245, 150, 98, 121, 147, 100, 108, 375, 343, 250, 162, 625, 243, 64, 96, 405 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

To make this a permutation of nonnegative integers, we subtract one from each run count except for the most significant run, e.g. a(12) = 10, as 12-1 = 11 = 1011 and 10 = 5^1 * 3^(1-1) * 2^(2-1).

LINKS

Table of n, a(n) for n=1..66.

Index entries for sequences that are permutations of the natural numbers

CROSSREFS

Inverse of A075160. a(n) = A075157(n-1)+1.

Sequence in context: A327173 A118315 A280577 * A191545 A064275 A080998

Adjacent sequences:  A075156 A075157 A075158 * A075160 A075161 A075162

KEYWORD

nonn

AUTHOR

Antti Karttunen, Sep 13 2002

STATUS

approved

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Last modified December 12 20:12 EST 2019. Contains 329961 sequences. (Running on oeis4.)