OFFSET
0,3
COMMENTS
The real 0's representations after the decimal point of the expansion of the square root of perfect squares are ignored. In other words for sqrt(4) = 2.0000..., the trailing 0's are ignored.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..1000
EXAMPLE
For n=14, the concatenated digits of sqrt(14) are The digit 0 in the 36th position of this string of digits so 36 is the 15th entry the table counting from the 0th entry.
MATHEMATICA
Join[{1}, Table[If[IntegerQ[Sqrt[n]], {{-1, -1}}, SequencePosition[ RealDigits[ Sqrt[n], 10, 100][[1]], {0}, 1]], {n, 100}][[All, 1]][[All, 1]]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Oct 02 2016 *)
PROG
(PARI) a(n)={if(n==0, 1, forstep(m=0, oo, 10, my(z=select(x->x==0, digits(sqrtint(100^m*n)), 1)); if(#z, return(z[1])); if(!m&&issquare(n), return(-1)) ))} \\ Andrew Howroyd, Dec 18 2024
CROSSREFS
KEYWORD
base,easy,sign
AUTHOR
Cino Hilliard, Dec 22 2006, corrected Jul 18 2007
STATUS
approved