OFFSET
1,1
COMMENTS
Squares of A334102 form a subsequence.
Among the first 12193 terms (terms < 2^31), there are terms with binary weights 2 - 16, except no terms with weight 13, 14 or 15. For example, 1025 is the first term with binary weight 2, and 65535 is the first term with binary weight 16.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..12193; all terms <= 2^31
EXAMPLE
63 = 7*9 is a term as both 7 and 9 are terms of A334102.
65535 = 3*5*17*257 is a term as it is a product of four Fermat primes, thus in four steps all odd primes can be eliminated with p -> (p-1) map.
MATHEMATICA
Position[Array[Length@NestWhileList[# - #/FactorInteger[#][[-1, 1]] &, #, # != 2^IntegerExponent[#, 2] &] - 1 &, 225], 4][[All, 1]] (* Michael De Vlieger, Apr 30 2020 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Apr 14 2020
STATUS
approved