A317726 Length of runs of terms in A104381 which differ only in the last decimal place.

4, 4, 2, 3, 3, 2, 2, 3, 2, 3, 4, 1, 1, 3, 1, 2, 2, 2, 1, 4, 1, 3, 2, 1, 3, 2, 2, 2, 1, 1, 3, 2, 2, 2, 1, 2, 2, 1, 2, 1, 1, 3, 2, 2, 3, 1, 2, 2, 2, 2, 2, 1, 3, 2, 1, 2, 2, 3, 1, 3, 3, 1, 2, 1, 1, 3, 1, 1, 2, 1, 2, 2, 1, 1, 1, 1, 1, 4, 1, 3, 1, 1, 3, 2, 2, 1, 1, 2, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 1, 3, 1, 3, 2, 1, 2

Offset

1,1

Links

Table of n, a(n) for n=1..105.

Example

a(11) = 4 because there are four elements in A104381 which differ from each other only in their last digit: 101, 103, 107, and 109.

Mathematica

Length /@ SplitBy[QuotientRemainder[#, 10] & /@ {1}~Join~Select[Range[1200], PowerMod[10, # - 1, #] == 1 &], First] (* Michael De Vlieger, Aug 05 2018, after Harvey P. Dale at A104381 *)

Crossrefs

Cf. A104381.

Sequence in context: A375187 A276149 A146899 * A031351 A068923 A222295

Adjacent sequences: A317723 A317724 A317725 * A317727 A317728 A317729

Keyword

nonn,base

Author

Alexander R. Povolotsky, Aug 05 2018

Extensions

More terms from Michael De Vlieger, Aug 05 2018

Status

approved