|
|
A071595
|
|
Odd numbers k such that the number of 1's in binary representation of k equals omega(k), the number of distinct primes in the factorization of k.
|
|
3
|
|
|
33, 65, 129, 273, 385, 513, 1025, 1155, 1281, 2049, 2065, 2145, 4097, 4161, 4641, 8193, 8195, 8211, 8225, 8265, 8385, 8449, 9345, 10241, 16905, 17409, 21505, 24585, 32775, 32785, 32835, 32865, 33033, 33285, 33345, 33825, 34881, 36865, 36993
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
EXAMPLE
|
129 = 10000001 in base 2 and 129 = 3*43 hence 129 is in the sequence.
|
|
MATHEMATICA
|
Select[Range[1, 37000, 2], DigitCount[#, 2, 1] == PrimeNu[#] &] (* Amiram Eldar, Jan 11 2020*)
|
|
PROG
|
(PARI) for(n=1, 80000, if(sum(i=1, length(binary(n)), component(binary(n), i))==-(-1)^n*omega(n), print1(n, ", ")))
|
|
CROSSREFS
|
|
|
KEYWORD
|
base,easy,nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|