This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
a(n) = fromdigits(digits((10^n-1)/9, 9));
a(1) = 11_bij9 = 1*9^1 + 1*9^0 = 9+1 = 10. a(2) = 121_bij9 = 1*9^2 + 2*9^1 + 1*9^0 = 81+18+1 = 100. a(3) = 1331_bij9 = 1*9^3 + 3*9^2 + 3*9^1 + 1*9^0 = 729+243+27+1 = 1000. a(7) = 19731371_bij9 = 9*(9*(9*(9*(9*(9*(9*1+9)+7)+3)+1)+3)+7)+1 = 10^7.
b:= proc(n) local d, l, m; m:= n; l:= "";
while m>0 do d:= irem(m, 9, 'm');
if d=0 then d:=9; m:= m-1 fi; l:= d, l
od; parse(cat(l))
end:
a:= n-> b(10^n):
seq(a(n), n=0..23);
A325203(n)=A052382(10^n) \\ M. F. Hasler, Jan 13 2020
FromDigits /@ IntegerDigits[10^Range[0, 9], 2] (* Jayanta Basu, Jul 12 2013 *)
a(n)=subst(Pol(binary(10^n)),x,10)
a(n) = fromdigits(binary(10^n)); \\ Michel Marcus, Apr 27 2022
def a(n): return int(bin(10**n)[2:]) print([a(n) for n in range(12)]) # Michael S. Branicky, Apr 27 2022
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