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A341261 Numbers that occur twice in the Wythoff ceiling array (A341260). 3
10, 23, 26, 31, 44, 57, 60, 65, 68, 78, 81, 86, 99, 112, 115, 120, 133, 146, 149, 154, 157, 167, 170, 175, 178, 188, 201, 204, 209, 212, 222, 225, 230, 243, 256, 259, 264, 277, 290, 293, 298, 301, 311, 314, 319, 332, 345, 348, 353, 366, 379, 382, 387, 390 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

No term occurs more than twice. Conjecture: the difference sequence, (13,3,5,13,13,3,5,...) has only 4 distinct terms: 3,5,10,13.

LINKS

Table of n, a(n) for n=1..54.

EXAMPLE

10 is in rows 1 and 4; 23 is in rows 2 and 9; 26 is in rows 1 and 10.

MATHEMATICA

W[n_, k_] := Fibonacci[k + 1] Ceiling[n*GoldenRatio] + (n - 1) Fibonacci[k];

t = Table[W[n - k + 1, k], {n, 500}, {k, n, 1, -1}] // Flatten; (* A341260 *)

s = Sort[t]; ss = s[[Select[Range[Length[s]] - 1, s[[#]] == s[[# + 1]] &]]]  (* A341261 *)

CROSSREFS

Cf. A341260.

Sequence in context: A214959 A054095 A125618 * A154033 A275238 A140674

Adjacent sequences:  A341258 A341259 A341260 * A341262 A341263 A341264

KEYWORD

nonn

AUTHOR

Clark Kimberling, Feb 09 2021

STATUS

approved

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Last modified December 1 16:44 EST 2021. Contains 349430 sequences. (Running on oeis4.)