A331881 a(n) is the first n-digit substring to occur n times in the decimal expansion of the fractional part of Pi.

1, 26, 446, 2796, 86538, 872117, 1591292, 66416662

Offset

1,2

Links

Table of n, a(n) for n=1..8.

Example

a(1) = 1, because '1' is the first 1-digit string appearing 1 time (at position 1);
a(2) = 26, because '26' is the first 2-digit string appearing 2 times (at positions 6 and 21);
a(3) =  446, because '446' is the first 3-digit string appearing 3 times (at positions 125, 182 and 217);
and so on.

Crossrefs

Cf. A000796, A197123.

Cf. A331882 (the number of digits needed to find the repeated n-digit strings).

Sequence in context: A024438 A025999 A028058 * A024170 A028042 A023956

Adjacent sequences: A331878 A331879 A331880 * A331882 A331883 A331884

Keyword

base,nonn,hard,more

Author

Stijn Dierckx, Jan 30 2020

Status

approved