[go: up one dir, main page]

login
A147764
Elias omega coded prime numbers represented in decimal.
2
8, 12, 84, 92, 236, 244, 2628, 2636, 2652, 2676, 2684, 5524, 5540, 5548, 5564, 5588, 5612, 5620, 11532, 11548, 11556, 11580, 11596, 11620, 11652, 11668, 11676, 11692, 11700, 11716, 11772, 24076, 24100, 24108, 24148, 24156, 24180, 24204, 24220
OFFSET
1,1
COMMENTS
The sequence in binary begins:
2 1000
3 1100
5 1010100
7 1011100
The final 0 bit represents an exponent of 1.
Because this is a prefix code, there is a one-to-one mapping between the integers and integers representing their factors, provided that the coded factors and exponents are adequately delimited, such as by inserting additional 0 bits.
For example, 75600 = 2^4 * 3^3 * 5^2 * 7 is representable as 100^101000 110^110 101010^100 101110^0 -> 1001010000110110010101010001011100 = 9946354780 decimal.
This representation is unambiguous because, e.g., the incorrect reading 1001010000110 splits as 100101000 0110 or 100^101000 0^110 -> 2^4 * 1^3, which is clearly wrong.
CROSSREFS
Sequence in context: A002288 A216711 A137232 * A226259 A162466 A098664
KEYWORD
base,easy,nonn
AUTHOR
Reikku Kulon, Nov 11 2008
STATUS
approved