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
Examples
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.
Crossrefs
Cf. A104381.
Programs
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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 *)
Extensions
More terms from Michael De Vlieger, Aug 05 2018