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A228988
Smallest missing number in first 10^n digits after the decimal point in the expansion of Pi.
4
0, 12, 103, 1001, 10000, 14523, 106945, 1001823, 10007363, 100023783, 1000020346
OFFSET
1,2
EXAMPLE
a(1) = 0 because 0 is missing in the first 10^1 = 10 digits after the decimal point in the expansion of Pi, that is, .1415926535...
Leading zeros do not count. Thus each of the digit-strings "0", "1", "2", ..., "14522" is present in the first 10^6 digits after the decimal point, but "14523" is not, so a(6) = 14523. - Robert Israel, Oct 19 2015
MATHEMATICA
Do[With[{r = ToString[FromDigits[Rest[RealDigits[Pi, 10, 10^k][[1]]]]]}, Do[If[StringPosition[r, ToString[n]] == {}, Print[n]; k = k + 1; Break[]], {n, 0, 10000000}]], {k, 7}]
PROG
(Python)
start = 0
for a in range(1, 10):
....with open("pi-billion.txt", "r") as f:
........g = f.read(10**a)
....while g.find(str(start)) != -1:
........start += 1
....print(a, start)
# http://stuff.mit.edu/afs/sipb/contrib/pi/pi-billion.txt
# David Consiglio, Jr., Oct 25 2014
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Shyam Sunder Gupta, Sep 10 2013
EXTENSIONS
More terms from David Consiglio, Jr., Oct 25 2015
a(10)-a(11) from Giovanni Resta, Aug 10 2019
STATUS
approved