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.

Showing 1-3 of 3 results.

A319394 Number T(n,k) of partitions of n into exactly k positive Fibonacci numbers; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 2, 1, 1, 0, 1, 1, 2, 1, 1, 0, 0, 2, 2, 2, 1, 1, 0, 0, 1, 3, 2, 2, 1, 1, 0, 1, 1, 2, 4, 2, 2, 1, 1, 0, 0, 1, 3, 3, 4, 2, 2, 1, 1, 0, 0, 2, 2, 4, 4, 4, 2, 2, 1, 1, 0, 0, 1, 3, 4, 5, 4, 4, 2, 2, 1, 1, 0, 0, 0, 3, 5, 5, 6, 4, 4, 2, 2, 1, 1
Offset: 0

Views

Author

Alois P. Heinz, Sep 18 2018

Keywords

Comments

T(n,k) is defined for n,k >= 0. The triangle contains only the terms with k <= n. T(n,k) = 0 for k > n.

Examples

			T(14,3) = 2: 851, 833.
T(14,4) = 5: 8321, 8222, 5531, 5522, 5333.
T(14,5) = 6: 83111, 82211, 55211, 53321, 53222, 33332.
T(14,6) = 8: 821111, 551111, 533111, 532211, 522221, 333311, 333221, 332222.
T(14,7) = 7: 8111111, 5321111, 5222111, 3332111, 3322211, 3222221, 2222222.
T(14,8) = 6: 53111111, 52211111, 33311111, 33221111, 32222111, 22222211.
Triangle T(n,k) begins:
  1;
  0, 1;
  0, 1, 1;
  0, 1, 1, 1;
  0, 0, 2, 1, 1;
  0, 1, 1, 2, 1, 1;
  0, 0, 2, 2, 2, 1, 1;
  0, 0, 1, 3, 2, 2, 1, 1;
  0, 1, 1, 2, 4, 2, 2, 1, 1;
  0, 0, 1, 3, 3, 4, 2, 2, 1, 1;
  0, 0, 2, 2, 4, 4, 4, 2, 2, 1, 1;
  0, 0, 1, 3, 4, 5, 4, 4, 2, 2, 1, 1;
  0, 0, 0, 3, 5, 5, 6, 4, 4, 2, 2, 1, 1;
  0, 1, 1, 2, 4, 7, 6, 6, 4, 4, 2, 2, 1, 1;
  0, 0, 1, 2, 5, 6, 8, 7, 6, 4, 4, 2, 2, 1, 1;
  ...

Links

Crossrefs

Columns k=0-10 give: A000007, A010056 (for n>0), A319395, A319396, A319397, A319398, A319399, A319400, A319401, A319402, A319403.
Row sums give A003107.
T(2n,n) gives A136343.
Cf. A000045, A281689, A319503.

Programs

  • Maple
    h:= proc(n) option remember; `if`(n<1, 0, `if`((t->
      issqr(t+4) or issqr(t-4))(5*n^2), n, h(n-1)))
    end:
b:= proc(n, i) option remember; `if`(n=0 or i=1, x^n,
      b(n, h(i-1))+expand(x*b(n-i, h(min(n-i, i)))))
    end:
T:= n-> (p-> seq(coeff(p, x, i), i=0..n))(b(n, h(n))):
seq(T(n), n=0..20);
  • Mathematica
    T[n_, k_] := SeriesCoefficient[1/Product[(1 - y x^Fibonacci[j]) + O[x]^(n+1) // Normal, {j, 2, n+1}], {x, 0, n}, {y, 0, k}];
Table[T[n, k], {n, 0, 40}, {k, 0, n}] // Flatten (* Jean-François Alcover, May 28 2020 *)
h[n_] := h[n] = If[n < 1, 0, If[Function[t, IntegerQ@Sqrt[t + 4] || IntegerQ@Sqrt[t - 4]][5 n^2], n, h[n - 1]]];
b[n_, i_, t_] := b[n, i, t] = If[n == 0, 1, If[i < 1 || t < 1, 0, b[n, h[i - 1], t] + b[n - i, h[Min[n - i, i]], t - 1]]];
T[n_, k_] :=  b[n, h[n], k] - b[n, h[n], k - 1];
Table[T[n, k], {n, 0, 20}, {k, 0, n}] // Flatten (* Jean-François Alcover, Dec 07 2020, after Alois P. Heinz *)

Formula

T(n,k) = [x^n y^k] 1/Product_{j>=2} (1-y*x^A000045(j)).
Sum_{k=1..n} k * T(n,k) = A281689(n).
T(A000045(n),n) = A319503(n).

A098641 Number of partitions of the n-th Fibonacci number into Fibonacci numbers.

Original entry on oeis.org

1, 1, 1, 2, 3, 6, 14, 41, 157, 803, 5564, 53384, 718844, 13783708, 380676448, 15298907733, 902438020514, 78720750045598, 10220860796171917, 1986422867300209784, 580763241873718042562, 256553744608217295298827, 171912553856721407543178940, 175350753369071026461010505478
Offset: 0

Views

Author

Marcel Dubois de Cadouin (dubois.ml(AT)club-internet.fr), Oct 27 2004

Keywords

Comments

a(n) = A003107(A000045(n)).

Examples

			n=6: A000045(6)=8, a(6) = #{8, 5+3, 5+2+1, 5+1+1+1, 3+3+2, 3+3+1+1, 3+2+2+1, 3+2+1+1+1, 3+1+1+1+1+1, 2+2+2+2, 2+2+2+1+1, 2+2+1+1+1+1, 2+1+1+1+1+1+1, 1+1+1+1+1+1+1+1} = 14; the other partitions of 8 into parts with at least one non-Fibonacci number: 7+1, 6+2, 6+1+1, 4+4, 4+3+1, 4+2+2, 4+2+1+1 and 4+1+1+1+1.

Links

Crossrefs

Cf. A000041, A000045, A065033, A072214, A098642, A098643, A098644, A319503.

Programs

  • Mathematica
    cl = CoefficientList[ Series[1/Product[(1 - x^Fibonacci[i]), {i, 2, 21}], {x, 0, 10950}], x]; cl[[ Table[ Fibonacci[i] + 1, {i, 21}] ]] (* Robert G. Wilson v, Apr 25 2005 *)

Formula

a(n) = A098642(n) + A098643(n) + A098644(n).

Extensions

Corrected and extended by Reinhard Zumkeller, Apr 24 2005
a(15)-a(21) from Robert G. Wilson v, Apr 25 2005
Entry revised by N. J. A. Sloane, Mar 29 2006
a(0), a(22)-a(23) from Alois P. Heinz, Sep 20 2018

A319435 Number of partitions of n^2 into exactly n nonzero squares.

Original entry on oeis.org

1, 1, 0, 1, 1, 1, 4, 4, 9, 16, 24, 52, 83, 152, 305, 515, 959, 1773, 3105, 5724, 10255, 18056, 32584, 58082, 101719, 179306, 317610, 552730, 962134, 1683435, 2899064, 4995588, 8638919, 14746755, 25196684, 43082429, 72959433, 123554195, 209017908, 351164162
Offset: 0

Views

Author

Alois P. Heinz, Sep 18 2018

Keywords

Examples

			a(0) = 1: the empty partition.
a(1) = 1: 1.
a(2) = 0: there is no partition of 4 into exactly 2 nonzero squares.
a(3) = 1: 441.
a(4) = 1: 4444.
a(5) = 1: 94444.
a(6) = 4: (25)44111, (16)(16)1111, (16)44444, 999441.
a(7) = 4: (25)(16)41111, (25)444444, (16)(16)44441, (16)999411.
a(8) = 9: (49)9111111, (36)(16)441111, (36)4444444, (25)(25)911111, (25)(16)944411, (25)9999111, (16)(16)(16)94111, (16)9999444, 99999991.

Links

Crossrefs

Cf. A243148, A259254, A319503.

Programs

  • Maple
    h:= proc(n) option remember; `if`(n<1, 0,
      `if`(issqr(n), n, h(n-1)))
    end:
b:= proc(n, i, t) option remember; `if`(n=0, 1, `if`(i<1 or
      t<1, 0, b(n, h(i-1), t)+b(n-i, h(min(n-i, i)), t-1)))
    end:
a:= n-> (s-> b(s$2, n)-`if`(n=0, 0, b(s$2, n-1)))(n^2):
seq(a(n), n=0..40);
  • Mathematica
    h[n_] := h[n] = If[n < 1, 0, If[Sqrt[n] // IntegerQ, n, h[n - 1]]];
b[n_, i_, t_] := b[n, i, t] = If[n == 0, 1, If[i < 1 || t < 1, 0, b[n, h[i - 1], t] + b[n - i, h[Min[n - i, i]], t - 1]]];
a[n_] := Function[s, b[s, s, n] - If[n == 0, 0, b[s, s, n - 1]]][n^2];
a /@ Range[0, 40] (* Jean-François Alcover, Nov 06 2020, after Alois P. Heinz *)
  • SageMath
    # uses[GeneralizedEulerTransform(n, a) from A338585], slow.
def A319435List(n): return GeneralizedEulerTransform(n, lambda n: n^2)
print(A319435List(10)) # Peter Luschny, Nov 12 2020

Formula

a(n) = A243148(n^2,n).
Showing 1-3 of 3 results.

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