A045863 - OEIS

A045863

Numbers whose square has initial digit '9'.

3, 30, 31, 95, 96, 97, 98, 99, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 949, 950, 951, 952, 953, 954, 955, 956, 957, 958, 959, 960, 961, 962, 963, 964, 965, 966, 967, 968, 969, 970, 971, 972, 973, 974, 975, 976

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

id9[n_]:=Module[{min=Floor[Sqrt[9*10^n]], max=Floor[Sqrt[10*10^n]]}, Select[ Range[ min, max], First[IntegerDigits[#^2]]==9&]]; Flatten[ Table[ id9[n], {n, 0, 5}]] (* Harvey P. Dale, May 29 2013 *)

PROG

(PARI) list(lim)=my(v=List()); for(d=1, 2*#digits(lim\=1), for(n=sqrtint(9*10^(d-1)-1)+1, min(sqrtint(10^d-1), lim), listput(v, n))); Vec(v) \\ Charles R Greathouse IV, Nov 03 2021

CROSSREFS

Cf. A045793.

Sequence in context: A344430 A217395 A077679 * A121023 A124520 A350814

Adjacent sequences: A045860 A045861 A045862 * A045864 A045865 A045866

KEYWORD

nonn,base,easy

AUTHOR

Jeff Burch

STATUS

approved