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 1-5 of 5 results.

A215580 Partial sums of A215602.

Original entry on oeis.org

2, 5, 17, 45, 122, 320, 842, 2205, 5777, 15125, 39602, 103680, 271442, 710645, 1860497, 4870845, 12752042, 33385280, 87403802, 228826125, 599074577, 1568397605, 4106118242, 10749957120, 28143753122, 73681302245, 192900153617, 505019158605, 1322157322202, 3461452808000, 9062201101802, 23725150497405, 62113250390417, 162614600673845
Offset: 0

Views

Author

J. M. Bergot, Aug 16 2012

Keywords

Comments

Dividing the terms of this sequence by Fibonacci or Lucas numbers yields symmetric sets of remainders of determinable lengths. For F(n) beginning at n=3: (a) F(2n) will have a set of remainders of length 2n in which the sum of the remainders is 3*(F(2n)-n). Example for F(2*6)=144: the set of remainders is {2,5,17,45,122,32,122,45,17,5,2,0} with 2*6=12 terms and a sum of 3*(144-6)=414. (b) For F(2n+1) there will be 2*(2n+1) terms having a sum equal to (2n+1)*(F(2n+1)-3). Example for F(2*4+1)=34: the remainders are {2,5,7,11,20,14,26,29,31,29,26,14,20,11,17,5,2,0} with 2*9 terms and a sum of 9*(34-1)=279.
Using Lucas numbers starting at n=2: (a) L(2n) has 4n remainders with sum (2n+1)*(L(2n)-6*n). Example for n=4 giving L(2*4)=47, has remainders {2,5,17,45,28,38,43,43,43,38,28,45,17,5,2,0} with a sum of (8+1)*(47)-6*4=399. (B) For L(2n+1) the length of the period is 2*(2n+1) and the sum of the remainders is 4*L(2n+1)-3*(2n+1). Example for n=3 for L(2*3+1)=29 has remainders {2,5,17,16,6,1,11,6,16,17,5,2,0} with length 2*7 and sum of terms 4*29-3*7=95.

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{3, 0, -3, 1}, {2, 5, 17, 45}, 35] (* Paolo Xausa, Feb 22 2024 *)

Formula

a(2n) = L(4*n)-2, a(2*n+1) = L(4*n+2)-1, where L() are the Lucas numbers A000032.
G.f. ( -2+x-2*x^2 ) / ( (x-1)*(1+x)*(x^2-3*x+1) ). - R. J. Mathar, Aug 21 2012
a(n) = A005248(n+1)-A000034(n). - R. J. Mathar, Aug 21 2012

Extensions

Edited by N. J. A. Sloane, Aug 17 2012

A005970 Partial sums of squares of Lucas numbers.

Original entry on oeis.org

1, 10, 26, 75, 196, 520, 1361, 3570, 9346, 24475, 64076, 167760, 439201, 1149850, 3010346, 7881195, 20633236, 54018520, 141422321, 370248450, 969323026, 2537720635, 6643838876, 17393796000, 45537549121, 119218851370
Offset: 1

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Author

Keywords

References

  • Alfred Brousseau, Fibonacci and Related Number Theoretic Tables, Fibonacci Association, San Jose, CA, 1972, p. 20.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Maple
    lucas := proc(n) option remember: if n=1 then RETURN(1) fi: if n=2 then RETURN(3) fi: lucas(n-1)+lucas(n-2) end: l[0] := 0: for i from 1 to 50 do l[i] := l[i-1]+lucas(i)^2; printf(`%d,`,l[i]) od: # James Sellers, May 29 2000
  • Mathematica
    Accumulate[LucasL[Range[30]]^2] (* Harvey P. Dale, Dec 06 2019 *)

Formula

a(n) - a(n-1) = A001254(n).
G.f.: (1+7*x-4*x^2)/((1-x)*(1+x)*(1-3*x+x^2)). - Simon Plouffe in his 1992 dissertation
From Amiram Eldar, Jan 13 2022: (Start)
a(n) = Sum_{k=1..n} L(k)^2, where L(k) is the k-th Lucas number (A000032).
a(n) = 3*a(n-1) - 3*a(n-3) + a(n-4), for n > 4.
a(n) = L(n)*L(n+1) - 2 = A215602(n) - 2. (End)

Extensions

More terms from James Sellers, May 29 2000
Definition clarified by Harvey P. Dale, Dec 06 2019

A075269 Product of Lucas numbers and inverted Lucas numbers: a(n)=A000032(n)*A075193(n).

Original entry on oeis.org

2, -3, 12, -28, 77, -198, 522, -1363, 3572, -9348, 24477, -64078, 167762, -439203, 1149852, -3010348, 7881197, -20633238, 54018522, -141422323, 370248452, -969323028, 2537720637, -6643838878, 17393796002, -45537549123, 119218851372, -312119004988, 817138163597
Offset: 0

Views

Author

Mario Catalani (mario.catalani(AT)unito.it), Sep 11 2002

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(2 + x + 2x^2)/(1 + 2x - 2x^2 - x^3), {x, 0, 30}], x]
    LinearRecurrence[{-2,2,1},{2,-3,12},30] (* Harvey P. Dale, Jun 30 2022 *)
  • PARI
    a(n)=1+(-1)^n*(fibonacci(2*n)+fibonacci(2*n+2))

Formula

a(n) = 1 + (-1)^n*A002878(n).
From Michael Somos, Apr 07 2003: (Start)
G.f.: (2+x+2x^2)/((1+3x+x^2)(1-x)).
a(n) = -3a(n-1) - a(n-2)+5 = -2a(n-1) + 2a(n-2) + a(n-3) = a(-1-n). (End)
Sum_{n>=0} 1/a(n) = sqrt(5)/10. - Amiram Eldar, Jan 15 2022
a(n) = (-1)^n*A215602(n). - R. J. Mathar, Jul 09 2024
a(n) - a(n-1) = (-1)^n* A054888(n), n>0. - R. J. Mathar, Jul 09 2024

A348591 a(n) = L(n)*L(n+1) mod F(n+2) where F=A000045 is the Fibonacci numbers and L = A000032 is the Lucas numbers.

Original entry on oeis.org

0, 1, 0, 3, 5, 3, 18, 3, 52, 3, 141, 3, 374, 3, 984, 3, 2581, 3, 6762, 3, 17708, 3, 46365, 3, 121390, 3, 317808, 3, 832037, 3, 2178306, 3, 5702884, 3, 14930349, 3, 39088166, 3, 102334152, 3, 267914293, 3, 701408730, 3, 1836311900, 3, 4807526973, 3, 12586269022, 3, 32951280096, 3, 86267571269, 3
Offset: 0

Views

Author

J. M. Bergot and Robert Israel, Jan 25 2022

Keywords

Examples

			a(5) = L(5)*L(6) mod F(7) = 11*18 mod 13 = 3.
		

Crossrefs

Programs

  • Maple
    F:= combinat:-fibonacci:
    L:= n -> F(n-1)+F(n+1):
    map(n -> L(n)*L(n+1) mod F(n+2), [$0..30]);
  • Mathematica
    a[n_] := Mod[LucasL[n] * LucasL[n + 1], Fibonacci[n + 2]]; Array[a, 50, 0] (* Amiram Eldar, Jan 26 2022 *)
  • Python
    from gmpy2 import fib, lucas2
    def A348591(n): return (lambda x,y:int(x[0]*x[1] % y))(lucas2(n+1),fib(n+2)) # Chai Wah Wu, Jan 26 2022

Formula

a(n) = 3 if n >= 3 is odd.
a(n) = A000045(n+2)-3 if n >= 2 is even.
a(n) + a(n+1) - 3*a(n+2) - 3*a(n+3) + a(n+4) + a(n+5) = 0 for n >= 2.
G.f.: -x*(2*x^5-5*x^3-x-1)/((x+1)*(x^2+x-1)*(x^2-x-1)). - Alois P. Heinz, Jan 26 2022

A216243 Partial sums of the squares of Lucas numbers (A000032).

Original entry on oeis.org

4, 5, 14, 30, 79, 200, 524, 1365, 3574, 9350, 24479, 64080, 167764, 439205, 1149854, 3010350, 7881199, 20633240, 54018524, 141422325, 370248454, 969323030, 2537720639, 6643838880, 17393796004, 45537549125, 119218851374, 312119004990, 817138163599, 2139295485800
Offset: 0

Views

Author

R. J. Mathar, Mar 14 2013

Keywords

Crossrefs

Cf. A001654.

Programs

  • Maple
    A001254 := proc(n)
            A000032(n)^2 ;
    end proc;
    A := proc(n)
            add( A001254(i),i=0..n) ;
    end proc:
  • Mathematica
    Accumulate[LucasL[Range[0,30]]^2] (* or *) LinearRecurrence[{3,0,-3,1},{4,5,14,30},30] (* Harvey P. Dale, Oct 13 2019 *)

Formula

a(n) = Sum_{i=0..n} A001254(i) = A002878(n) +A176040(n) = A215602(n)+2.
G.f.: ( -4+7*x+x^2 ) / ( (x-1)*(1+x)*(x^2-3*x+1) ).
a(n) = -7*A064831(n) -A064831(n-1) +4*A064831(n+1).
a(n) = L(2*n+1) + 2 + (-1)^n, for L(n) the Lucas sequence A000032(n). - Greg Dresden, Jan 26 2021
Showing 1-5 of 5 results.