OFFSET
1,4
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..16384 (First 210 terms from Diana L. Mecum).
EXAMPLE
The first 7 terms written in binary are [1,1,0,10,0,0,0]. The 8th term gives the number of earlier terms with the same number of 1's in their binary representation as 8 (which is 1000 in binary, for one 1). a(8) = 3 because there are three terms among the first 7 terms with one binary 1 (terms with one 1: 1, 1 and 2).
MATHEMATICA
Fold[Append[#1, Block[{b = DigitCount[#2, 2, 1]}, {#, DigitCount[#, 2, 1]} &@ Count[#1[[All, -1]], k_ /; k == b]]] &, {{1, 1}}, Range[2, 99]][[All, 1]] (* Michael De Vlieger, Nov 18 2017 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Leroy Quet, Jan 10 2006
EXTENSIONS
More terms from Diana L. Mecum, May 29 2007
STATUS
approved