A376356 Positions of numbers in A000462 that end in 2.

2, 5, 8, 12, 17, 20, 23, 26, 30, 33, 38, 41, 44, 47, 50, 53, 57, 60, 63, 68, 71, 74, 80, 83, 86, 90, 93, 96, 99, 103, 107, 110, 113, 117, 122, 125, 128, 132, 138, 141, 144, 148, 155, 158, 161, 165, 170, 173, 176, 179, 183, 188, 192, 195, 198

Offset

1,1

Comments

Every positive integer is in exactly one of the following sequences: A376354, A376355, or this sequence.

Conjecture: {a(n+1) - a(n) : n >= 1} = {3,4,5,6,7,8,9}. (See related conjectures at A376354 and A376355.)

Links

Table of n, a(n) for n=1..55.

Mathematica

a[n_, poly_] := FromDigits[FoldList[{Mod[#[[1]], #2], Quotient[#[[1]], #2]} &, {n, 0}, Reverse[Map[(poly - 2)  #  (# - 1)/2 + # &, Range[Floor[Sqrt[2  n]]]]]][[All, 2]]]
t3 = Map[a[#, 3] &, Range[200]]; (* A000462 *)
m = Mod[t3, 10]
Table[Flatten[Position[m, r]], {r, 0, 2}]
p0 = Flatten[Position[m, 0]]  (* A376354 *)
p1 = Flatten[Position[m, 1]]  (* A376355 *)
p2 = Flatten[Position[m, 2]]  (* this sequence *)
(* Peter J. C. Moses, Sep 20 2024 *)

Crossrefs

Cf. A000462, A376354, A376355, A376357.

Sequence in context: A108577 A272719 A297834 * A036789 A330188 A214047

Adjacent sequences: A376353 A376354 A376355 * A376357 A376358 A376359

Keyword

nonn,base

Author

Clark Kimberling, Sep 25 2024

Status

approved