cp's OEIS Frontend

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.

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A259556 Rectangular array, read by antidiagonals: T(h,k) = u(h) + v(k), where u = A000201 (lower Wythoff numbers), v = A001950 (upper Wythoff numbers), and h >= 1, k >= 1.

Original entry on oeis.org

3, 6, 5, 8, 8, 6, 11, 10, 9, 8, 14, 13, 11, 11, 10, 16, 16, 14, 13, 13, 11, 19, 18, 17, 16, 15, 14, 13, 21, 21, 19, 19, 18, 16, 16, 14, 24, 23, 22, 21, 21, 19, 18, 17, 16, 27, 26, 24, 24, 23, 22, 21, 19, 19, 18, 29, 29, 27, 26, 26, 24, 24, 22, 21, 21, 19, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21
Offset: 1

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Author

Clark Kimberling, Jul 22 2015

Keywords

Examples

			Northwest corner:
3    6    8    11   14   16   19
5    8    10   13   16   18   21
6    9    11   14   17   19   22
8    11   13   16   19   22   24
10   13   15   18   21   23   26
11   14   16   19   22   24   27
T(2,3) = u(2) + v(3) = 3 + 7 = 10.
		

Crossrefs

Programs

  • Mathematica
    r = GoldenRatio; z = 12;
    u[n_] := u[n] = Floor[n*r]; v[n_] := v[n] = Floor[n*r^2];
    s[m_, n_] := s[m, n] = u[m] + v[n]; t = Table[s[m, n], {m, 1, z}, {n, 1, z}]
    TableForm[t] (* A259556 array *)
    Table[s[n - k + 1, k], {n, z}, {k, n, 1, -1}] // Flatten (* A259556 sequence *)

A295540 Number of ways of writing n as the sum of a lower Wythoff number (A000201) and an upper Wythoff number (A001950), when zero is included in both sequences.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 3, 1, 4, 2, 3, 5, 1, 5, 5, 2, 7, 3, 5, 8, 1, 9, 5, 5, 10, 2, 9, 9, 3, 12, 5, 8, 13, 1, 13, 10, 5, 15, 5, 11, 15, 2, 17, 9, 9, 18, 3, 16, 15, 5, 20, 8, 13, 21, 1, 22, 13, 10, 23, 5, 19, 20, 5, 25, 11, 15, 26, 2, 25, 19, 9, 28, 9, 20, 27, 3, 30, 16, 15, 31, 5, 27, 25, 8, 33, 13, 21, 34, 1, 34, 23, 13, 36, 10, 27, 33, 5, 38, 19, 20, 39, 5, 35, 30, 11, 41, 15, 27, 41, 2, 43, 25, 19, 44, 9, 36, 37, 9, 46, 20, 27
Offset: 0

Views

Author

Paul D. Hanna, Nov 30 2017

Keywords

Comments

Note that floor(n*phi) and floor(n*phi^2), for n>=1, form Beatty sequences.

Examples

			G.f.: A(x) = 1 + x + x^2 + 2*x^3 + x^4 + 2*x^5 + 3*x^6 + x^7 + 4*x^8 + 2*x^9 + 3*x^10 + 5*x^11 + x^12 + 5*x^13 + 5*x^14 + 2*x^15 + 7*x^16 + 3*x^17 + 5*x^18 + 8*x^19 + x^20 + 9*x^21 + 5*x^22 + 5*x^23 + 10*x^24 + 2*x^25 + 9*x^26 + 9*x^27 + 3*x^28 + 12*x^29 + 5*x^30 + 8*x^31 + 13*x^32 + x^33 + 13*x^34 + 10*x^35 + 5*x^36 + 15*x^37 + 5*x^38 + 11*x^39 + 15*x^40 + 2*x^41 + 17*x^42 + 9*x^43 + 9*x^44 + 18*x^45 + 3*x^46 + 16*x^47 + 15*x^48 + 5*x^49 + 20*x^50 +...+ a(n)*x^n +...
such that A(x) = WL(x) * WU(x) where
WL(x) = 1 + x + x^3 + x^4 + x^6 + x^8 + x^9 + x^11 + x^12 + x^14 + x^16 + x^17 + x^19 + x^21 + x^22 + x^24 + x^25 + x^27 + x^29 + x^30 +...+ x^A000201(n) +...
WU(x) = 1 + x^2 + x^5 + x^7 + x^10 + x^13 + x^15 + x^18 + x^20 + x^23 + x^26 + x^28 + x^31 + x^34 + x^36 + x^39 + x^41 + x^44 + x^47 + x^49 +...+ x^A001950(n) +...
Terms equal 1 only at positions:
[0, 1, 2, 4, 7, 12, 20, 33, 54, 88, 143, 232, 376, ..., Fibonacci(n+1)-1, ...].
		

Crossrefs

Programs

  • PARI
    {a(n) = my(phi = (1 + sqrt(5))/2, WL=1, WU=1);
    WL = sum(m=0,floor(n/phi)+1, x^floor(m*phi) +x*O(x^n));
    WU = sum(m=0,floor(n/phi^2)+1, x^floor(m*phi^2) +x*O(x^n));
    polcoeff(WL*WU,n)}
    for(n=0,120, print1(a(n),", "))

Formula

G.f.: [ Sum_{n>=0} x^floor(n*phi) ] * [ Sum_{n>=0} x^floor(n*phi^2) ], where phi = (1+sqrt(5))/2.
G.f.: [1 + Sum_{n>=1} x^A000201(n) ] * [1 + Sum_{n>=1} x^A001950(n) ], where A000201 and A001950 are the lower and upper Wythoff sequences, respectively.
a(Fibonacci(n+1)-1) = 1 for n>=1.
a(Fibonacci(n+2)-2) = Fibonacci(n) for n>=1.
Showing 1-2 of 2 results.