OFFSET
0,3
REFERENCES
D. E. Knuth, The Art of Computer Programming, vol. 4A, Combinatorial Algorithms, Section 7.2.1.5, p. 432, Problems 4 and 5.
LINKS
R. J. Mathar, Table of n, a(n) for n = 0..4460
MATHEMATICA
f[n_] := Block[{d = Prepend[IntegerDigits@ n, 0], a, b, w}, b = DeleteDuplicates@ d; a = Range[0, Length@ b]; w = FromDigits@ Flatten[Part[a, FirstPosition[b, #]] & /@ d]; w]; Take[Union@ Table[f[n^2], {n, 0, 320}], 42] (* Michael De Vlieger, Dec 09 2015, Version 10 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
N. J. A. Sloane, Nov 20 2006
EXTENSIONS
More terms from Franklin T. Adams-Watters, Nov 20 2006
STATUS
approved