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.
%I A307582 #15 Dec 05 2024 18:08:23
%S A307582 2,7,188,2264,27931,110808,23489363,97438020
%N A307582 Position of the first occurrence of (0, 1, ..., n-1) in the digits of Pi written in base n.
%C A307582 Position refers to the digit where there required sequence (0, ..., n-1) starts. Position = k means the digit '0' occurs as digit corresponding to the weight n-^k (and thereafter, the digit '1' will correspond to n^-(k+1) etc): e.g., the first digit after the decimal point has position 1.
%F A307582 A307581(n) <= a(n) <= A307583(n).
%e A307582 Pi written in base 2 is 11.001...[2], so the first "01" occurs at position a(2) = 2.
%e A307582 Pi written in base 3 is 10.010211012...[3], we see that the first occurrence of the string "012" is at position a(3) = 7.
%e A307582 Pi written in base 4 is 3.02100333...[4]; the string of digits "0123" does not occur until position a(4) = 188.
%o A307582 (PARI) A307582(n,x=Pi,m=Mod(sum(i=1,n-1,i*n^(n-1-i)),n^n))={for(k=0,oo,x\n^-k==m&&return(k-n+1))} \\ Ensure sufficient precision of the argument x = Pi.
%Y A307582 Cf. A307581 (first occurrence of any permutation of 0 .. n-1, in base-n digits of Pi).
%Y A307582 Cf. A307583 (start of last permutation of {0 .. n-1} not to occur earlier, in base-n digits of Pi).
%Y A307582 Cf. A068987 (occurrence of 123...n in decimal digits of Pi), A121280.
%K A307582 nonn,base,more,hard
%O A307582 2,1
%A A307582 _M. F. Hasler_, Apr 15 2019
%E A307582 a(7)-a(9) from _Chai Wah Wu_, Apr 07 2020