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A307583 Position where the last of all n! permutations of { 0 .. n-1 } occurs in the digits of Pi written in base n. 3
2, 82, 961, 15136 (list; graph; refs; listen; history; text; internal format)



By "permutation of { 0 .. n-1 }" we mean a string of n distinct digits. "The last" means the permutation which occurs for the first time later than all other permutations.

Position = k means that the string starts with the digit corresponding to the weight n^-k; e.g., the first digit after the decimal point has position 1.


Table of n, a(n) for n=2..5.


Pi written in base 2 is 11.001...[2], so the first "10" occurs at position 0 (starting with the digit of units) and "01" occurs later at position a(2) = 2.

Pi written in base 3 is 10.010211012...[3], we see that the first permutation of 0..2 to appear is "102", at position 2; then "021" at position 3, then "012" at position 7, then "201" at position 12, then "120" at position 39, and finally "210", the last partition not occurring earlier, at position 82 = a(3).

Pi written in base 4 is 3.02100333...[4]; the first permutation of 0..3 is "3012" at position 0 (starting at units digit '3'), the next distinct permutation to occur is "2031" at position 27 etc.; the last permutation not to occur earlier is "2310" at position 961 = a(4).


(PARI) A307583(n, x=Pi, m=n^n, S=[])={for(k=n-2, oo, #Set(d=digits(x\n^-k%m, n)) < n-1 && next; #Set(d)==n || vecsort(d)==[1..n-1] || next; setsearch(S, d) && next; printf("%d: %d, ", k-n+1, Vec(d, -n)); S=setunion(S, [d]); #S==n!&&return(k-n+1))}


Cf. A307581 (first start of any permutation of 0 .. n-1 in base-n digits of Pi).

Cf. A307582 (first occurrence of "01...(n-1)" in digits of Pi written in base n).

Cf. A068987 (occurrence of 123...n in decimal digits of Pi), A121280.

Sequence in context: A343588 A259308 A202965 * A061994 A332584 A197641

Adjacent sequences:  A307580 A307581 A307582 * A307584 A307585 A307586




M. F. Hasler, Apr 15 2019



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Last modified May 24 19:38 EDT 2022. Contains 354043 sequences. (Running on oeis4.)