This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A386625 #9 Aug 04 2025 06:25:59 %S A386625 1,2,4,3,6,9,5,10,15,12,8,16,24,20,25,13,26,39,32,40,18,21,42,63,52, %T A386625 65,30,7,34,68,102,84,105,48,14,64,55,110,165,136,170,78,35,104,27,89, %U A386625 178,267,220,275,126,56,168,45,50,144,288,432,356,445,204,91,272,72,80,11 %N A386625 Rectangular array R, read by descending antidiagonals: (row m) = increasing sequence of numbers m*F(n), n>=2, without duplicates, where F = A000045 (Fibonacci numbers); see Comments. %C A386625 Every positive integer appears exactly once. Every non-Fibonacci prime appears in the first column. Except for initial terms, every row is a row of the Wythoff array, A035513. %F A386625 (row 1) = (1,2,3,5,8,13,...) = Fibonacci numbers, {F(n), n>=2}, and for m>1, %F A386625 (row m) = numbers m*F(n) that are not h*F(k) for any h<m and k>=2. %e A386625 Corner: %e A386625 1 2 3 5 8 13 21 34 55 %e A386625 4 6 10 16 26 42 68 110 178 %e A386625 9 15 24 39 63 102 165 267 432 %e A386625 12 20 32 52 84 136 220 356 576 %e A386625 25 40 65 105 170 275 445 720 1165 %e A386625 18 30 48 78 126 204 330 534 864 %e A386625 7 14 35 56 91 147 238 385 623 %e A386625 64 104 168 272 440 712 1152 864 3016 %e A386625 27 45 72 117 189 306 495 801 1296 %e A386625 50 80 130 210 340 550 890 1440 2330 %e A386625 11 22 33 88 143 231 374 605 979 %e A386625 36 60 96 156 252 408 660 1068 1728 %e A386625 Row 4 is obtained from 4*(row 1) by removing 4 and 8. %t A386625 ClearAll[rArray] %t A386625 rArray[rows_, cols_] := Module[{fibs, R = {}, used = <||>, row, val, f, m}, %t A386625 fibs = Map[Fibonacci, Range[2, cols + rows]]; %t A386625 Table[row = {}; %t A386625 Do[val = m*f; If[! KeyExistsQ[used, val], AppendTo[row, val]; %t A386625 used[val] = True;], {f, fibs}]; Take[row, cols], {m, rows}]]; %t A386625 Grid[rArray[16, 12], Frame -> All] (* array *) %t A386625 r[m_, n_] := rArray[12, 12][[m]][[n]]; %t A386625 Table[r[n - k + 1, k], {n, 1, 12}, {k, n, 1, -1}] // Flatten (*sequence*) %t A386625 (* _Peter J. C. Moses_, Jul 27 2025 *) %Y A386625 Cf. A000045, A005086 (counts removed duplicates), A035513, A386214. %K A386625 nonn,tabl %O A386625 1,2 %A A386625 _Clark Kimberling_, Jul 27 2025