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A089998
Smallest square with Hamming weight n (i.e., with exactly n 1's when written in binary).
9
0, 1, 9, 25, 169, 121, 441, 1521, 2025, 5625, 24025, 47089, 109561, 32761, 393129, 851929, 1540081, 6275025, 15327225, 27258841, 41925625, 127893481, 243204025, 385611769, 998244025, 1979449081, 4823441401, 12870221809, 34324602361
OFFSET
0,3
COMMENTS
A000120(a(n)) = n.
LINKS
FORMULA
a(n) = A231897(n)^2. - Hugo Pfoertner, Dec 27 2022
MATHEMATICA
a = Table[0, {30}]; Do[c = Count[IntegerDigits[n^2, 2], 1]; If[ a[[c + 1]] == 0, a[[c + 1]] = n^2; Print[c, " = ", n^2]], {n, 1, 360000}] (* Robert G. Wilson v, Dec 03 2003 *)
Join[{0}, With[{s=DigitCount[Range[400000]^2, 2, 1]}, Flatten[Table[ Position[ s, _?(#==n&), 1, 1], {n, 30}]]]^2] (* Harvey P. Dale, Mar 03 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Nov 20 2003
EXTENSIONS
More terms from Robert G. Wilson v, Dec 03 2003
Offset corrected by Donovan Johnson, May 01 2012
STATUS
approved