A333359 Variation of Van Eck's sequence A181391: a(n+1) = the minimum positive offset m from a(n) such that the decimal concatenation of a(n-m), a(n-m+1), ..., a(n-m+k) = a(n), where k >= 0; a(n+1)=0 if no such m exists. Start with a(1)=0.

0, 0, 1, 0, 2, 0, 2, 2, 1, 6, 0, 5, 0, 2, 6, 5, 4, 0, 5, 3, 0, 3, 2, 9, 0, 4, 9, 3, 6, 14, 0, 6, 3, 5, 15, 0, 5, 3, 5, 2, 17, 0, 6, 11, 0, 3, 8, 0, 3, 3, 1, 42, 0, 5, 15, 20, 51, 0, 5, 5, 1, 10, 59, 0, 6, 22, 59, 4, 42, 17, 29, 48, 0, 9, 47, 0, 3, 27, 0, 3, 3, 1, 21, 75, 0, 6

Offset

1,5

Comments

The terms up to a(56) are the same as A181391 but vary from a(57) and beyond. After 10000 terms the smallest number not appearing is 332.

Links

Table of n, a(n) for n=1..86.

Brady Haran and N. J. A. Sloane, Don't Know (the Van Eck Sequence), Numberphile video (2019).

Example

a(42) = 0 as a(41) = 17, and neither '17' or adjacent sequence terms '1' and '7' appear earlier in the sequence.
a(57) = 51 as a(56) = 20, and the value '20' is the concatenation of a(5) = 2 and a(6) = 0, and a(5) is fifty-one terms back from a(56).

Crossrefs

Cf. A181391, A007908, A001704.

Sequence in context: A380106 A336891 A181391 * A350151 A341846 A262670

Adjacent sequences: A333356 A333357 A333358 * A333360 A333361 A333362

Keyword

nonn,base

Author

Scott R. Shannon, Mar 16 2020

Status

approved