OFFSET
1,2
COMMENTS
For the digit position in sqrt(n) at which the digit a(n) first appears, see A343740.
FORMULA
a(100^q*n) = a(n), q > 0. - Bernard Schott, Jul 24 2021
EXAMPLE
a(2)=8 because 8 is the last digit to appear in sqrt(2) = 1.414213562373095048...;
a(24)=0 because 0 is the last digit to appear in sqrt(24) = 4.898979485566356196394568149411782783931894961313340...
MATHEMATICA
Table[If[IntegerQ@ Sqrt@ n, -1, Function[s, FirstPosition[#, Max@ #][[1]] - 1 &@ Array[FirstPosition[s, #][[1]] &, 10, 0]]@ RealDigits[Sqrt[n], 10, 120][[1]]], {n, 84}] (* Michael De Vlieger, Jul 06 2021 *)
PROG
(Python 3.8+)
from math import isqrt
def A343739(n):
i = isqrt(n)
if i**2 == n:
return -1
m, dset = n, set()
for d in (int(s) for s in str(i)):
dset.add(d)
if len(dset) == 10:
return d
while len(dset) < 10:
m *= 100
d = isqrt(m) % 10
dset.add(d)
return d # Chai Wah Wu, Jul 07 2021
CROSSREFS
KEYWORD
sign,base
AUTHOR
Jon E. Schoenfield, Jul 05 2021
STATUS
approved