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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.

A385590 Triangle read by rows, based on Fibonacci numbers: Let i > 1 be such that F(i) <= n < F(i+1); i.e., i = A130233(n). Then T(n, k) = F(i-1)^2 + 1 - (i-1) mod 2 + (n - F(i)) * F(i-2) + (k-1) * F(i-1) where F(k) = A000045(k).

Original entry on oeis.org

1, 2, 3, 4, 6, 8, 5, 7, 9, 11, 10, 13, 16, 19, 22, 12, 15, 18, 21, 24, 27, 14, 17, 20, 23, 26, 29, 32, 25, 30, 35, 40, 45, 50, 55, 60, 28, 33, 38, 43, 48, 53, 58, 63, 68, 31, 36, 41, 46, 51, 56, 61, 66, 71, 76, 34, 39, 44, 49, 54, 59, 64, 69, 74, 79, 84, 37, 42, 47, 52, 57, 62, 67, 72, 77, 82, 87, 92, 65, 73, 81, 89, 97
Offset: 1

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Author

Werner Schulte, Jul 03 2025

Keywords

Comments

Conjecture: This triangle yields a permutation of the natural numbers.

Examples

			Triangle T(n, k) for 1 <= k <= n starts:
n\ k :   1   2   3   4   5   6   7   8   9  10  11  12  13
==========================================================
   1 :   1
   2 :   2   3
   3 :   4   6   8
   4 :   5   7   9  11
   5 :  10  13  16  19  22
   6 :  12  15  18  21  24  27
   7 :  14  17  20  23  26  29  32
   8 :  25  30  35  40  45  50  55  60
   9 :  28  33  38  43  48  53  58  63  68
  10 :  31  36  41  46  51  56  61  66  71  76
  11 :  34  39  44  49  54  59  64  69  74  79  84
  12 :  37  42  47  52  57  62  67  72  77  82  87  92
  13 :  65  73  81  89  97 105 113 121 129 137 145 153 161
  etc.
		

Crossrefs

Programs

  • PARI
    T(n, k) = i=1; for(j=1,n,if(j==fibonacci(i+1),i=i+1)); (fibonacci(i-1))^2+1-(i-1)%2 + (n-fibonacci(i))*fibonacci(i-2) + (k-1)*fibonacci(i-1)

Formula

Conjecture: Sum_{k=1..n} (-1)^k * binomial(n-1, k-1) * T(n, k) = 0 for n > 2 and (-1)^n for n < 3.