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A322643 Number of times the digit 2 appears in the first 10^n decimal digits of sqrt(2), sometimes called Pythagoras's constant, counting after the decimal point. 10
2, 8, 109, 1004, 9876, 100436, 1000208, 9998091, 99995645, 999987069 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

It is not known if sqrt(2) is normal, but the distribution of decimal digits found for the first 10^n digits of sqrt(2) shows no statistically significant departure from a uniform distribution.

LINKS

Table of n, a(n) for n=1..10.

Eric Weisstein's World of Mathematics, Pythagoras's Constant Digits.

MAPLE

a:=proc(n)

local digits, SQRT2, C, i;

digits:=10^n+100;

SQRT2:=convert(frac(evalf[digits](sqrt(2))), string)[2..digits-99];

C:=0;

for i from 1 to length(SQRT2) do

if SQRT2[i]="2" then C:=C+1; fi;

od;

return(C);

end;

MATHEMATICA

Table[DigitCount[IntegerPart[(Sqrt[2]-1)*10^10^n], 10, 2], {n, 1, 10}] (* Robert Price, Mar 29 2019 *)

CROSSREFS

Cf. A002193, A099293, A322641, A322642, A322644, A322645, A322646, A322647, A322648, A322649, A322650.

Sequence in context: A256398 A008926 A136468 * A178171 A132523 A012554

Adjacent sequences: A322640 A322641 A322642 * A322644 A322645 A322646

KEYWORD

nonn,base,more

AUTHOR

Martin Renner, Dec 21 2018

STATUS

approved

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Last modified December 8 19:12 EST 2022. Contains 358698 sequences. (Running on oeis4.)