|
|
A114344
|
|
Starting position of the first n in the decimal expansion of the square root of n, or -1 if n never appears.
|
|
0
|
|
|
1, 1, 5, 3, -1, 37, 39, 5, 2, -1, 89, 20, 52, 222, 319, 49, -1, 12, 99, 25, 144, 61, 41, 9, 109, -1, 145, 10, 268, 33, 189, 184, 155, 371, 45, 108, -1, 118, 26, 11, 149, 146, 108, 5, 235, 49, 299, 253, 32, -1, 103, 212, 120, 179, 353, 119, 225, 64, 10, 108, 104
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
LINKS
|
|
|
EXAMPLE
|
For n=5, sqrt(5) = 2.23606797749978969640917366873127623544...
5 occurs in the 37th position so 37 is the 6th entry in the table counting from the 0th entry.
|
|
PROG
|
(PARI) digitpos(n) = { local(x, y, r, dot); for(x=0, n, r=sqrt(x); if(issquare(x), y=find(Str(floor(r)), x), y=find(Str(r), x); dot=find(Str(r), "."); if(dot < y, y--); ); if(y, print1(y", "), print1(-1", ") ) ) }
find(str, match) = /* Revised 2007 */ { local(lnm, lns, tstr, vstr, x, j); vstr=Vec(Str(str)); match=Str(match); lns=length(str); lnm=length(match); for(x=1, lns-lnm+1, tstr=""; for(j=x, x+lnm-1, tstr=concat(tstr, vstr[j]); ); if(match==tstr, return(x)) ); return(0); }
|
|
CROSSREFS
|
|
|
KEYWORD
|
base,easy,sign
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|