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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A203860 G.f.: Product_{n>=1} (1 - Lucas(n)*x^n + (-1)^n*x^(2*n)) where Lucas(n) = A000204(n).

Original entry on oeis.org

1, -1, -4, -1, 1, 11, 7, 25, 18, -11, -1, 0, -325, -199, 122, -1364, -843, 550, 0, 11, 123, 0, 39650, 24476, -15126, 0, 271443, 164194, -103682, -1364, -1, -24476, 0, -9349, -123, -20633239, -12752043, 7881225, -843, 0, -226965629, -141422125, 88114450, 0, 1
Offset: 0

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Author

Paul D. Hanna, Jan 07 2012

Keywords

Comments

a(A093519(n)) = 0 where A093519 lists numbers that are not equal to the sum of two generalized pentagonal numbers.

Examples

			G.f.: A(x) = 1 - x - 4*x^2 - x^3 + x^4 + 11*x^5 + 7*x^6 + 25*x^7 +...
-log(A(x)) = x + 3*3*x^2/2 + 4*4*x^3/3 + 7*7*x^4/4 + 6*11*x^5/5 + 12*18*x^6/6 +...+ sigma(n)*A000204(n)*x^n/n +...
The g.f. equals the product:
A(x) = (1-x-x^2) * (1-3*x^2+x^4) * (1-4*x^3-x^6) * (1-7*x^4+x^8) * (1-11*x^5-x^10) * (1-18*x^6+x^12) *...* (1 - Lucas(n)*x^n + (-1)^n*x^(2*n)) *...
Positions of zeros form A093519:
[11,18,21,25,32,39,43,46,49,54,60,65,67,68,74,76,81,87,88,90,...]
which are numbers that are not the sum of two generalized pentagonal numbers.
		

Crossrefs

Programs

  • PARI
    /* Subroutine used in PARI programs below: */
    {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)}
    
  • PARI
    {a(n)=polcoeff(exp(sum(k=1, n, -sigma(k)*Lucas(k)*x^k/k)+x*O(x^n)), n)}
    
  • PARI
    {a(n)=polcoeff(prod(m=1, n, 1 - Lucas(m)*x^m + (-1)^m*x^(2*m) +x*O(x^n)), n)}

Formula

G.f.: exp( Sum_{n>=1} -sigma(n) * A000204(n) * x^n/n ).

A233359 a(n) = |{0 < k < n: L(k) + q(n-k) is prime}|, where L(k) is the k-th Lucas number (A000204), and q(.) is the strict partition function (A000009).

Original entry on oeis.org

0, 1, 1, 2, 3, 1, 2, 4, 2, 2, 3, 3, 2, 4, 3, 5, 1, 4, 5, 3, 1, 3, 3, 7, 3, 3, 4, 5, 2, 2, 9, 2, 4, 4, 9, 2, 6, 6, 6, 3, 3, 1, 5, 7, 4, 4, 5, 7, 4, 9, 5, 6, 4, 1, 5, 6, 11, 9, 4, 2, 5, 5, 4, 6, 8, 9, 12, 3, 7, 5, 4, 10, 6, 7, 6, 3, 5, 8, 4, 4, 4, 4, 7, 7, 5, 1, 4, 9, 7, 4, 8, 7, 6, 5, 2, 3, 7, 11, 5, 5
Offset: 1

Views

Author

Zhi-Wei Sun, Dec 08 2013

Keywords

Comments

Conjecture: a(n) > 0 for all n > 1.
We have verified this for n up to 60000.
Note that for n = 19976 there is no k = 0,...,n such that F(k) + q(n-k) is prime, where F(0), F(1), ... are the Fibonacci numbers.

Examples

			a(7) = 2 since L(1) + q(6) = 1 + 4 = 5 and L(6) + q(1) = 18 + 1 = 19 are both prime.
a(17) = 1 since L(13) + q(4) = 521 + 2 = 523 is prime.
a(21) = 1 since L(5) + q(16) = 11 + 32 = 43 is prime.
a(42) = 1 since L(22) + q(20) = 39603 + 64 = 39667 is prime.
a(54) = 1 since L(8) + q(46) = 47 + 2304 = 2351 is prime.
a(86) = 1 since L(67) + q(19) = 100501350283429 + 54 = 100501350283483 is prime.
		

Crossrefs

Programs

  • Mathematica
    a[n_]:=Sum[If[PrimeQ[LucasL[k]+PartitionsQ[n-k]],1,0],{k,1,n-1}]
    Table[a[n],{n,1,100}]

A272909 Numbers that are the product of two Lucas numbers L(i), for i >= 1, using the Lucas numbers as defined in A000204.

Original entry on oeis.org

1, 3, 4, 7, 9, 11, 12, 16, 18, 21, 28, 29, 33, 44, 47, 49, 54, 72, 76, 77, 87, 116, 121, 123, 126, 141, 188, 198, 199, 203, 228, 304, 319, 322, 324, 329, 369, 492, 517, 521, 522, 532, 597, 796, 836, 841, 843, 846, 861, 966, 1288, 1353, 1363, 1364, 1368, 1393
Offset: 1

Views

Author

Clark Kimberling, May 10 2016

Keywords

Comments

Conjecture: if c and d are consecutive terms, then d - c is a product of two Lucas numbers or a product of two Fibonacci numbers.

Crossrefs

Cf. A049997 (Fibonacci(i)*Fibonacci(j)), A000204.

Programs

  • Mathematica
    Take[Union@Flatten@Table[LucasL[i] LucasL[j], {i, 0, 15}, {j, i}], 60] (* adapted by Vincenzo Librandi, Sep 04 2016 *)

A101033 Triangle read by rows giving the coefficients of general sum formulas of n-th Lucas numbers (A000204). The k-th row (k>=1) contains T(i,k) for i=1 to 2*k-1, where T(i,k) satisfies L(n) = Sum_{k=1..n} Sum_{i=1..2*k-1} T(i,k) * C(n-k,i-1) * n^(n-k) / (n-1)!.

Original entry on oeis.org

1, 1, -2, -3, 2, 15, 51, 65, 27, 6, -148, -945, -2292, -2776, -1680, -405, 24, 2290, 19580, 71965, 145525, 175244, 125950, 50085, 8505, 120, -41676, -473072, -2340400, -6676835, -12132890, -14587261, -11619692, -5290005, -1752030, -229635, 720, 943908, 13132532, 81977672, 303352938, 740797855
Offset: 1

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Author

Keywords

Examples

			L(7)= (1/(7-1)!) * [ 7^(7-1) -{-1+2*(7-2)+3*C(7-2,2)}*7^(7-2) +{2+15*(7-3)+51*C(7-3,2)+65*C(7-3,3) +27*C(7-3,4)}*7^(7-3) -{-6+148*(7-4)+945*C(7-4,2)+2292*C(7-4,3)}*7^(7-4) +... ]
= (1/6!) * [ 7^6 -{-1+10+30}*7^5 +{2+60+306+260+27}*7^4 -{-6+444+2835+2292}*7^3 +{24+4580+19580}*7^2 -{-120+41676}*7 +{720} ] = (1/6!) * [ 7^6 -39*7^5 +655*7^4 -5565*7^3 +24184*7^2 -41556*7 +720 ]
= (1/720) * [ 117649 -655473 +1572655 -1908795 +1185016 -290892 +720 ] = 20880/720 = 29.
		

Crossrefs

A104765 Triangle T(n,k) read by rows: row n contains the first n Lucas numbers A000204.

Original entry on oeis.org

1, 1, 3, 1, 3, 4, 1, 3, 4, 7, 1, 3, 4, 7, 11, 1, 3, 4, 7, 11, 18, 1, 3, 4, 7, 11, 18, 29, 1, 3, 4, 7, 11, 18, 29, 47, 1, 3, 4, 7, 11, 18, 29, 47, 76, 1, 3, 4, 7, 11, 18, 29, 47, 76, 123, 1, 3, 4, 7, 11, 18, 29, 47, 76, 123, 199, 1, 3, 4, 7, 11, 18, 29, 47, 76, 123, 199, 322, 1, 3, 4, 7, 11
Offset: 1

Views

Author

Gary W. Adamson, Mar 24 2005

Keywords

Comments

Reading rows from the right to the left yields A104764.
Sequence B is called a reluctant sequence of sequence A, if B is triangle array read by rows: row number k coincides with first k elements of the sequence A. Sequence A104765 is the reluctant sequence of A000204. - Boris Putievskiy, Dec 14 2012

Examples

			First few rows of the triangle are:
  1;
  1, 3;
  1, 3, 4;
  1, 3, 4, 7;
  1, 3, 4, 7, 11;
  1, 3, 4, 7, 11, 18;
  ...
		

Crossrefs

Cf. A027961 (row sums).

Programs

  • Mathematica
    Table[LucasL[k], {n, 1, 10}, {k, 1, n}] // Flatten (* G. C. Greubel, Dec 21 2017 *)
    Module[{nn=20,luc},luc=LucasL[Range[nn]];Table[Take[luc,n],{n,nn}]]//Flatten (* Harvey P. Dale, Jul 10 2024 *)
  • PARI
    for(n=1,10, for(k=1,n, print1(fibonacci(k+1) + fibonacci(k-1), ", "))) \\ G. C. Greubel, Dec 21 2017

Formula

T(n,k) = A000204(k), 1<=k<=n.
T(n,k) = A104764(n,n-k+1).
a(n) = A000204(m), where m = n-t(t+1)/2, t = floor((-1+sqrt(8*n-7))/2). - Boris Putievskiy, Dec 14 2012
G.f.: (x*y*(2*x*y+1))/((x-1)*(x^2*y^2+x*y-1)). - Vladimir Kruchinin, Jun 21 2025

Extensions

Edited and extended by R. J. Mathar, Jul 23 2008

A153175 a(n) = L(7*n)/L(n) where L(n) = Lucas number A000204(n).

Original entry on oeis.org

29, 281, 6119, 101521, 1875749, 33281921, 599786069, 10745088481, 192933544679, 3461223997001, 62114818827629, 1114566304366081, 20000347407134669, 358889844987430121, 6440029487834912999, 115561554399692896321
Offset: 1

Views

Author

Artur Jasinski, Dec 20 2008

Keywords

Comments

All numbers in this sequence are:
congruent to 9 mod 10 (iff n is odd),
congruent to 1 mod 10 (iff n is even).

Crossrefs

Cf. A153177, A153179, A153180. [From R. J. Mathar, Oct 22 2010]

Programs

  • Magma
    [Lucas(7*n)/Lucas(n): n in [0..30]]; // G. C. Greubel, Dec 21 2017
  • Mathematica
    Table[LucasL[7*n]/LucasL[n], {n, 1, 50}]
  • PARI
    {lucas(n) = fibonacci(n+1) + fibonacci(n-1)};
    for(n=0,30, print1( lucas(7*n)/lucas(n), ", ")) \\ G. C. Greubel, Dec 21 2017
    

Formula

From R. J. Mathar, Oct 22 2010: (Start)
a(n) = +13*a(n-1) +104*a(n-2) -260*a(n-3) -260*a(n-4) +104*a(n-5) +13*a(n-6) -a(n-7).
G.f.: -x*(-29+96*x+550*x^2-290*x^3-200*x^4+16*x^5+x^6) / ( (1+x)*(x^2-3*x+1)*(x^2-18*x+1)*(x^2+7*x+1) ).
a(n) = A005248(n) +A087215(n) -(-1)^n*A056854(n) - (-1)^n. (End)

A153177 a(n) = L(9*n)/L(n) where L(n) = Lucas number A000204(n).

Original entry on oeis.org

76, 1926, 109801, 4769326, 230701876, 10716675201, 505618944676, 23714405408926, 1114769987764201, 52357935173823126, 2459933168462154076, 115560463558534156801, 5428954301161174383676, 255043991670277234750326
Offset: 1

Views

Author

Artur Jasinski, Dec 20 2008

Keywords

Comments

All numbers in this sequence are:
congruent to 1 mod 100 (iff n is congruent to 0 mod 3),
congruent to 26 mod 100 (iff n is congruent to 2 or 4 mod 6),
congruent to 76 mod 100 (iff n is congruent to 1 or 5 mod 6).

Crossrefs

Programs

  • Magma
    [Lucas(9*n)/Lucas(n): n in [0..30]]; // G. C. Greubel, Dec 21 2017
  • Mathematica
    Table[LucasL[9*n]/LucasL[n], {n, 1, 50}]
    LinearRecurrence[{34,714,-4641,-12376,12376,4641,-714,-34,1},{76,1926,109801,4769326,230701876,10716675201,505618944676,23714405408926,1114769987764201},20] (* Harvey P. Dale, Aug 12 2012 *)
  • PARI
    {lucas(n) = fibonacci(n+1) + fibonacci(n-1)};
    for(n=0,30, print1( lucas(9*n)/lucas(n), ", ")) \\ G. C. Greubel, Dec 21 2017
    

Formula

From R. J. Mathar, Oct 22 2010: (Start)
a(n) = 34*a(n-1) +714*a(n-2) -4641*a(n-3) -12376*a(n-4) +12376*a(n-5) +4641*a(n-6) -714*a(n-7) -34*a(n-8) +a(n-9).
G.f.: -x*(76-658*x-9947*x^2+13644*x^3+26020*x^4-5306*x^5-1372*x^6+42*x^7 +x^8) / ((x-1)*(x^2+18*x+1)*(x^2-47*x+1)*(x^2+3*x+1)*(x^2-7*x+1)).
a(n) = 1-(-1)^n*A087215(n) -(-1)^n*A005248(n) +A056854(n) +A087265(n). (End)

A153179 a(n) = L(11*n)/L(n) where L(n) = A000204(n).

Original entry on oeis.org

199, 13201, 1970299, 224056801, 28374454999, 3450736132801, 426236170575799, 52337681992411201, 6441140796368008699, 792018481913198430001, 97420733208491869044199, 11981539981561372141075201
Offset: 1

Views

Author

Artur Jasinski, Dec 20 2008

Keywords

Comments

All numbers in this sequence are:
congruent to 99 mod 100 (iff n is odd),
congruent to 1 mod 100 (iff n is even).

Crossrefs

Programs

  • Magma
    [Lucas(11*n)/Lucas(n): n in [0..30]]; // G. C. Greubel, Dec 21 2017
  • Mathematica
    Table[LucasL[11*n]/LucasL[n], {n, 1, 50}]
  • PARI
    {lucas(n) = fibonacci(n+1) + fibonacci(n-1)};
    for(n=0,30, print1( lucas(11*n)/lucas(n), ", ")) \\ G. C. Greubel, Dec 21 2017
    

Formula

From R. J. Mathar, Oct 22 2010: (Start)
a(n) = +89*a(n-1) +4895*a(n-2) -83215*a(n-3) -582505*a(n-4) +1514513*a(n-5) +1514513*a(n-6) -582505*a(n-7) -83215*a(n-8) +4895*a(n-9) +89*a(n-10) -a(n-11).
G.f.: -1 -1/(1+x) +(-2-47*x)/(x^2+47*x+1) +(2-3*x)/(x^2-3*x+1) +(-2-7*x)/(x^2+7*x+1) +(2-123*x)/(x^2-123*x+1) +(2-18*x)/(x^2-18*x+1).
a(n) = -(-1)^n -(-1)^n*A087265(n) +A005248(n) -(-1)^n*A056854(n) +A065705(n) +A087215(n). (End)

A166168 G.f.: exp( Sum_{n>=1} Lucas(n^2)*x^n/n ) where Lucas(n) = A000204(n).

Original entry on oeis.org

1, 1, 4, 29, 585, 34212, 5600397, 2490542953, 2968152042068, 9416588994339205, 79216509536543420965, 1762508872870620792746360, 103525263562786817866762466405, 16031370626878431551103688398524485
Offset: 0

Views

Author

Paul D. Hanna, Oct 08 2009

Keywords

Comments

Conjectured to consist entirely of integers.
The Lucas numbers (A000204) forms the logarithmic derivative of the Fibonacci numbers (A000045).
Note that Lucas(n^2) = [(1+sqrt(5))/2]^(n^2) + [(1-sqrt(5))/2]^(n^2).

Examples

			G.f.: A(x) = 1 + x + 4*x^2 + 29*x^3 + 585*x^4 + 34212*x^5 +...
log(A(x)) = x + 7*x^2/2 + 76*x^3/3 + 2207*x^4/4 + 167761*x^5/5 + 33385282*x^6/6 +...+ Lucas(n^2)*x^n/n +...
		

Crossrefs

Programs

  • Maple
    with(combinat): seq(coeff(series(exp(add((fibonacci(k^2-1)+fibonacci(k^2+1))*x^k/k,k=1..n)),x,n+1), x, n), n = 0 .. 15); # Muniru A Asiru, Dec 18 2018
  • Mathematica
    CoefficientList[Series[Exp[Sum[LucasL[n^2]*x^n/n, {n, 1, 200}]], {x, 0, 50}], x](* G. C. Greubel, May 06 2016 *)
  • PARI
    {a(n)=polcoeff(exp(sum(m=1,n,(fibonacci(m^2-1)+fibonacci(m^2+1))*x^m/m)+x*O(x^n)),n)}

Formula

a(n) = (1/n)*Sum_{k=1..n} Lucas(k^2)*a(n-k), a(0)=1.
Logarithmic derivative yields A166169.

A191988 Ordered sums 2*f+5*g, where f and g are Lucas numbers beginning at 1 (A000204).

Original entry on oeis.org

7, 11, 13, 17, 19, 21, 22, 23, 26, 27, 28, 29, 34, 37, 41, 42, 43, 49, 51, 56, 57, 61, 63, 69, 71, 73, 77, 78, 91, 92, 93, 96, 98, 99, 104, 109, 112, 113, 114, 126, 129, 147, 148, 149, 151, 153, 157, 159, 167, 172, 181, 184, 187, 203, 207, 237, 239, 241, 242
Offset: 1

Views

Author

Clark Kimberling, Jun 20 2011

Keywords

Crossrefs

Programs

  • Mathematica
    c = 2; d = 5; f[n_] := LucasL[n];
    g[n_] := c*f[n]; h[n_] := d*f[n];
    t[i_, j_] := h[i] + g[j];
    u = Table[t[i, j], {i, 1, 20}, {j, 1, 20}];
    v = Union[Flatten[u]]    (* A191988 *)
    t1[i_, j_] := If[g[i] - h[j] > 0, g[i] - h[j], 0]
    u1 = Table[t1[i, j], {i, 1, 20}, {j, 1, 20}];
    v1 = Union[Flatten[u1]]  (* A191989: c*f(i)-d*f(j) *)
    g1[n_] := d*f[n]; h1[n_] := c*f[n];
    t2[i_, j_] := If[g1[i] - h1[j] > 0, g1[i] - h1[j], 0]
    u2 = Table[t2[i, j], {i, 1, 20}, {j, 1, 20}];
    v2 = Union[Flatten[u2]]  (* A191990: d*f(i)-c*f(j) *)
    v3 = Union[v1, v2]       (* A191991 *)
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