OFFSET
0,1
MATHEMATICA
f[n_] := DigitCount[n, 2, 1]; a[n_] := f[f[n+1]] - f[f[n]]; Array[a, 100, 0] (* Amiram Eldar, Jul 23 2023 *)
CROSSREFS
KEYWORD
sign,base
AUTHOR
N. J. A. Sloane, Nov 12 2005
EXTENSIONS
Definition corrected by N. J. A. Sloane, Feb 14 2018
STATUS
approved