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A124606 Position of the first 6 in the decimal expansion of the square root of n, or -1 if 6 never appears. 0
-1, -1, 9, 12, -1, 4, 39, 2, 13, -1, 3, 4, 3, 2, 5, 10, -1, 8, 5, 14, 30, 8, 2, 27, 12, -1, 39, 4, 8, 6, 14, 3, 2, 6, 37, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, 6, 30, 19, 41, 6, 4, 21, 17, 2, 2, 6, 8, 20, 27, -1, 3, 11, 18, 4, 4, 3, 4, 48, 18, 2, 2, 24, 6, 6, 26, 20, -1, 16, 23, 3, 30, 5, 34, 11, 13, 4, 12, 5, 2, 2, 4, 25, 13, 10, 12, -1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..100.

PROG

(PARI) digitpos(n, m) = /* m-th digit in sqrt expansions */ { local(x, y, r, dot); default(realprecision, 1000); for(x=0, n, r = sqrt(x); if(issquare(x), y=find(Str(floor(r)), m), y=find(Str(r), m); 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

Sequence in context: A159003 A196509 A269026 * A110647 A335168 A295486

Adjacent sequences:  A124603 A124604 A124605 * A124607 A124608 A124609

KEYWORD

base,easy,sign

AUTHOR

Cino Hilliard, Dec 22 2006, corrected Jul 18 2007

STATUS

approved

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Last modified June 23 07:38 EDT 2021. Contains 345395 sequences. (Running on oeis4.)