A380419 Split A377091 into sublists consisting of runs of terms with the same sign. Then a(n) = 1 if terms in the n-th sublist form an arithmetic progression with common difference 1 or -1, 0 otherwise.

1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1

Offset

1

Links

Paolo Xausa, Table of n, a(n) for n = 1..1000

Example

A377091 with terms grouped by sign begins:
  (0) (1 2) (-2 -1) (3 4 5) (-4 -3) (6 7 8) (-8 -7 -6 -5 -9 -10 -11 -12) ...
And the corresponding terms of the present sequence are therefore:
   1   1      1      1        1      1        0 ...

Mathematica

(* A377091list is defined at A377091 *)
Map[Boole[# == Range[Min[#], Max[#]] || # == Range[Max[#], Min[#], -1]] &, Most[SplitBy[A377091list[2000], Sign]]]

Crossrefs

Cf. A377091, A379882, A380417, A380418, A380423, A380510.

Sequence in context: A175608 A285467 A194679 * A111940 A129572 A070950

Adjacent sequences: A380416 A380417 A380418 * A380420 A380421 A380422

Keyword

nonn

Author

Paolo Xausa, Jan 24 2025

Status

approved