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A109600 Numbers n such that number of 1's in binary representation of n equals the number of digits required to write the prime factors of n. 1
2, 6, 9, 10, 17, 22, 26, 28, 38, 42, 50, 54, 60, 69, 70, 74, 78, 82, 90, 92, 98, 99, 102, 114, 116, 131, 133, 134, 135, 137, 145, 146, 150, 153, 154, 161, 165, 169, 170, 172, 193, 194, 195, 202, 209, 210, 212, 220, 225, 226, 234, 242, 248, 259, 265, 275, 278, 282 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
708588 has 13 1's in base 2 and 13 digits in its factorization. What is the next term in this sequence with more 1's and digits?
2881008 has 14 1's in base 2 and 14 digits in its factorization. - Harvey P. Dale, Jul 04 2023
LINKS
EXAMPLE
54=110110 in base 2 and 54=2*3*3*3, hence 54 is in the sequence.
MATHEMATICA
Select[Range[2, 300], DigitCount[#, 2, 1]==Total[IntegerLength[#[[1]]]#[[2]]&/@ FactorInteger[ #]]&] (* Harvey P. Dale, Jul 04 2023 *)
CROSSREFS
Cf. A076649.
Sequence in context: A243373 A085304 A015843 * A370802 A370810 A071814
KEYWORD
base,easy,nonn
AUTHOR
Jason Earls, Jul 30 2005
STATUS
approved

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Last modified April 14 00:20 EDT 2024. Contains 371652 sequences. (Running on oeis4.)