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 1-9 of 9 results.

A010074 a(n) = sum of base-7 digits of a(n-1) + sum of base-7 digits of a(n-2).

Original entry on oeis.org

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

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Author

Keywords

Comments

The digital sum analog (in base 7) of the Fibonacci recurrence. - Hieronymus Fischer, Jun 27 2007
a(n) and Fib(n)=A000045(n) are congruent modulo 6 which implies that (a(n) mod 6) is equal to (Fib(n) mod 6) = A082117(n-1) (for n>0). Thus (a(n) mod 6) is periodic with the Pisano period A001175(6)=24. - Hieronymus Fischer, Jun 27 2007
For general bases p>2, the inequality 2<=a(n)<=2p-3 holds (for n>2). Actually, a(n)<=11=A131319(7) for the base p=7. - Hieronymus Fischer, Jun 27 2007

Crossrefs

Programs

  • Mathematica
    nxt[{a_,b_}]:={b,Total[IntegerDigits[a,7]]+Total[IntegerDigits[b,7]]}; Transpose[NestList[nxt,{0,1},80]][[1]] (* Harvey P. Dale, Oct 12 2013 *)

Formula

Periodic from n=3 with period 24. - Franklin T. Adams-Watters, Mar 13 2006
From Hieronymus Fischer, Jun 27 2007: (Start)
a(n) = a(n-1)+a(n-2)-6*(floor(a(n-1)/7)+floor(a(n-2)/7)).
a(n) = floor(a(n-1)/7)+floor(a(n-2)/7)+(a(n-1)mod 7)+(a(n-2)mod 7).
a(n) = (a(n-1)+a(n-2)+6*(A010876(a(n-1))+A010876(a(n-2))))/7.
a(n) = Fib(n)-6*sum{1A000045(n). (End)

Extensions

Incorrect comment removed by Michel Marcus, Apr 29 2018

A082115 Fibonacci sequence (mod 3).

Original entry on oeis.org

0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2, 1, 0, 1, 1, 2, 0, 2, 2
Offset: 0

Views

Author

Eric W. Weisstein, Apr 03 2003

Keywords

Crossrefs

Programs

Formula

Sequence is periodic with Pisano period 8.
a(n) = 1-floor(n/8)+floor((n-1)/8)+floor((n-3)/8)-2*floor((n-4)/8) +2*floor((n-5)/8)-floor((n-7)/8). - Hieronymus Fischer, Jul 01 2007
a(n) = 1+((n mod 8)+((n+1)mod 8)-2*((n+3)mod 8)+2*((n+4)mod 8) -((n+5)mod 8) -((n+7)mod 8))/8. - Hieronymus Fischer, Jul 01 2007
G.f.: (x+x^2+2x^3+2x^5+2x^6+x^7)/(1-x^8). - Hieronymus Fischer, Jul 01 2007
a(n) = A131295(n) mod 3 (for n>0). - Hieronymus Fischer, Jul 01 2007

Extensions

Added a(0)=0. - Jon Perry, Sep 15 2013

A082116 Fibonacci sequence (mod 5).

Original entry on oeis.org

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

Views

Author

Eric W. Weisstein, Apr 03 2003

Keywords

Comments

This sequence contains the complete set of residues modulo 5. See A079002. - Michel Marcus, Jan 31 2020

References

  • S. Vajda, Fibonacci and Lucas numbers and the Golden Section, Ellis Horwood Ltd., Chichester, 1989. See p. 88. - N. J. A. Sloane, Feb 20 2013

Crossrefs

Programs

Formula

Sequence is periodic with Pisano period 20.
a(n) = 2 + ((n mod 20) - ((n - 1) mod 20) - ((n - 3) mod 20) - ((n - 4) mod 20) + 3*((n - 5) mod 20) - 3*((n - 6) mod 20) + 2*((n - 8) mod 20) - 3*((n - 9) mod 20) + 4*((n - 10) mod 20) - 4*((n - 11) mod 20) + ((n - 13) mod 20) + ((n - 14) mod 20) + 2*((n - 15) mod 20) - 2*((n - 16) mod 20) - 2*((n - 18) mod 20) + 3*((n - 19) mod 20))/20. - Hieronymus Fischer, Jun 30 2007
G.f.: (x + x^2 + 2x^3 + 3x^4 + 3x^6 + 3x^7 + x^8 + 4x^9 + 4x^11 + 4x^12 + 3x^13 + 2x^14 + 2x^16 + 2x^17 + 4x^18 + x^19)/(1 - x^20), not reduced. - Hieronymus Fischer, Jun 30 2007
a(n) = A010073(n) mod 5. - Hieronymus Fischer, Jun 30 2007
G.f.: -x*(1 + x + x^2 + 2*x^3 + 3*x^6 - x^7 - 2*x^8 - x^4 + x^9 + 4*x^10 + x^11) / ( (x - 1) * (x^4 + x^3 + x^2 + x + 1) * (x^8 - x^6 + x^4 - x^2 + 1) ). - R. J. Mathar, Jul 14 2012

Extensions

Added a(0)=0 from Vincenzo Librandi, Feb 04 2014

A079344 F(n) mod 8, where F(n) = A000045(n) is the n-th Fibonacci number.

Original entry on oeis.org

0, 1, 1, 2, 3, 5, 0, 5, 5, 2, 7, 1, 0, 1, 1, 2, 3, 5, 0, 5, 5, 2, 7, 1, 0, 1, 1, 2, 3, 5, 0, 5, 5, 2, 7, 1, 0, 1, 1, 2, 3, 5, 0, 5, 5, 2, 7, 1, 0, 1, 1, 2, 3, 5, 0, 5, 5, 2, 7, 1, 0, 1, 1, 2, 3, 5, 0, 5, 5, 2, 7, 1, 0, 1, 1, 2, 3, 5, 0, 5, 5, 2, 7, 1, 0, 1, 1, 2, 3, 5, 0, 5, 5, 2, 7, 1, 0, 1, 1, 2, 3, 5, 0, 5, 5
Offset: 0

Views

Author

Jon Perry, Jan 04 2003

Keywords

Comments

This sequence does not contain the complete set of residues modulo 8. See A079002. - Michel Marcus, Jan 31 2020

Examples

			a(8) = F(8) mod 8 = 21 mod 8 = 5.
		

Crossrefs

Programs

  • Magma
    [Fibonacci(n) mod 8: n in [0..100]]; // Vincenzo Librandi, Feb 04 2014
  • Mathematica
    Mod[Fibonacci[Range[0,110]],8] (* or *) LinearRecurrence[ {1,0,0,-1,1,0,0,-1,1},{0,1,1,2,3,5,0,5,5},110] (* Harvey P. Dale, Jan 16 2014 *)
  • PARI
    for (n=0,100,print1(fibonacci(n)%8","))
    

Formula

Sequence is periodic with Pisano period 12 = A001175(8).
G.f.: -x*(1+x^2+x^3+3*x^4+6*x^6-5*x^5+x^7) / ( (x-1)*(x^2-x+1)*(1+x+x^2)*(x^4-x^2+1) ). - R. J. Mathar, Aug 08 2012

Extensions

Edited by N. J. A. Sloane, Dec 06 2008 at the suggestion of R. J. Mathar

A280154 a(n) = 5*Lucas(n).

Original entry on oeis.org

10, 5, 15, 20, 35, 55, 90, 145, 235, 380, 615, 995, 1610, 2605, 4215, 6820, 11035, 17855, 28890, 46745, 75635, 122380, 198015, 320395, 518410, 838805, 1357215, 2196020, 3553235, 5749255, 9302490, 15051745, 24354235, 39405980, 63760215, 103166195, 166926410, 270092605, 437019015
Offset: 0

Views

Author

Bruno Berselli, Dec 27 2016

Keywords

Comments

Fibonacci sequence beginning 10, 5.
After 5, the sequence provides the 3rd column of the rectangular array in A213590.
After 5, all terms belong to A191921 because a(n) = Lucas(n+4) - 3*Lucas(n-1).
From G. C. Greubel, Dec 27 2016: (Start)
{a(n) mod 3} yields (1,2,0,2,2,1,0,1), repeated, and is given as A082115.
{a(n) mod 6} yields (4,5,3,2,5,1,0,1,1,2,3,5,2,1,3,4,1,5,0,5,5,4,3,1) and is given as A082117. (End)

Crossrefs

Subsequence of A084176.
Cf. A022088: 5*Fibonacci(n).
Cf. A022359: Lucas(n+5) + Lucas(n-5).
Cf. sequences with formula Fibonacci(n+k) + Fibonacci(n-k): A006355 (k=0, without the initial 1), A000032 (k=1), A022086 (k=2), A022112 (k=3, with an initial 4), A022090 (k=4), this sequence (k=5), A022352 (k=6).

Programs

  • Magma
    [5*Lucas(n): n in [0..40]];
    
  • Maple
    F := n -> combinat:-fibonacci(n):
    seq(F(n+5) + F(n-5), n=0..38); # Peter Luschny, Dec 29 2016
  • Mathematica
    Table[5 LucasL[n], {n, 0, 40}]
  • PARI
    vector(40, n, n--; fibonacci(n+5)+fibonacci(n-5))
    
  • Sage
    def A280154():
        x, y = 10, 5
        while True:
            yield x
            x, y = y, x + y
    a = A280154(); print([next(a) for  in range(39)]) # _Peter Luschny, Dec 29 2016

Formula

G.f.: 5*(2 - x)/(1 - x - x^2).
a(n) = a(n-1) + a(n-2) for n>1.
a(n) = Fibonacci(n+5) + Fibonacci(n-5), with Fibonacci(-k) = -(-1)^k*Fibonacci(k) for the negative indices.

A004699 a(n) = floor(Fibonacci(n)/6).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 2, 3, 5, 9, 14, 24, 38, 62, 101, 164, 266, 430, 696, 1127, 1824, 2951, 4776, 7728, 12504, 20232, 32736, 52968, 85704, 138673, 224378, 363051, 587429, 950481, 1537910, 2488392, 4026302, 6514694, 10540997, 17055692, 27596690, 44652382
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A000045.

Programs

  • Magma
    [Floor(Fibonacci(n)/6): n in [0..40]]; // Vincenzo Librandi, Jul 10 2012
    
  • Maple
    seq(floor(combinat[fibonacci](n)/6), n=0..40); # Muniru A Asiru, Oct 10 2018
  • Mathematica
    Table[Floor[Fibonacci[n]/6], {n, 0, 50}] (* Vincenzo Librandi, Jul 10 2012 *)
    CoefficientList[Series[x^6 (1 + x + x^4 + x^6 + x^9 + x^10 + x^11 + x^14 + x^15 + x^17 + x^18)/((1 - x - x^2) (1 - x^24)), {x, 0, 50}], x] (* Stefano Spezia, Oct 11 2018 - corrected by G. C. Greubel, May 21 2019 *)
  • PARI
    vector(50, n, n--; fibonacci(n)\6) \\ G. C. Greubel, Oct 09 2018
    
  • Sage
    [floor(fibonacci(n)/6) for n in (0..40)] # G. C. Greubel, May 21 2019

Formula

G.f.: x^6*(1 + x + x^4 + x^6 + x^9 + x^10 + x^11 + x^14 + x^15 + x^17 + x^18)/((1 - x - x^2)*(1 - x^24)). [Corrected by G. C. Greubel, May 21 2019]
a(n) = (A000045(n) - A082117(n))/6. - R. J. Mathar, Jul 14 2012

A269701 Cyclic Fibonacci sequence, restricted to maximum=6.

Original entry on oeis.org

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

Views

Author

Gabriel Osorio, Mar 04 2016

Keywords

Comments

Sequence has a period of 24.

Examples

			For n = 6; F(5) + F(4) equals 8 then F(6) = 8 - 6 = 2.
		

Crossrefs

Cf. A000045 (Fibonacci numbers), A082117.

Programs

  • Erlang
    fibocy(1) -> 1;
    fibocy(2) -> 1;
    fibocy(N) when N > 1 ->
       Tmp = fibocy(N-1) + fibocy(N-2),
       if Tmp > 6 -> Tmp - 6;
          true -> Tmp
       end.
  • Maple
    A269701 := proc(n)
        option remember;
        if n <=5 then
            combinat[fibonacci](n) ;
        else
            a := procname(n-1)+procname(n-2) ;
            if a > 6 then
                a-6;
            else
                a;
            end if;
        end if;
    end proc: # R. J. Mathar, Apr 16 2016
  • Mathematica
    Table[Mod[Fibonacci[n], 6], {n, 100}] /. 0 -> 6 (* Alonso del Arte, Mar 28 2016 *)
    PadRight[{0},120,{6,1,1,2,3,5,2,1,3,4,1,5,6,5,5,4,3,1,4,5,3,2,5,1}] (* Harvey P. Dale, May 13 2019 *)

Formula

F(n) = F(n-1) + F(n-2) with F(0) = 0 and F(1) = 1 and F(n) = F(n-1) + F(n-2) - 6 if F(n-1) + F(n-2) > 6.
G.f.: ( -x *(1 +x +2*x^2 +3*x^3 +5*x^4 +2*x^5 +x^6 +3*x^7 +4*x^8 +x^9 +5*x^10 +6*x^11 +5*x^12 +5*x^13 +4*x^14 +3*x^15 +x^16 +4*x^17 +5*x^18 +3*x^19 +2*x^20 +5*x^21 +x^22 +6*x^23) ) / ( (x-1) *(1+x+x^2) *(1+x) *(1-x+x^2) *(1+x^2) *(x^4-x^2+1) *(1+x^4) *(x^8-x^4+1) ). - R. J. Mathar, Apr 16 2016

A160101 Lodumo_6 of Fibonacci numbers.

Original entry on oeis.org

0, 1, 7, 2, 3, 5, 8, 13, 9, 4, 19, 11, 6, 17, 23, 10, 15, 25, 16, 29, 21, 14, 35, 31, 12, 37, 43, 20, 27, 41, 26, 49, 33, 22, 55, 47, 18, 53, 59, 28, 39, 61, 34, 65, 45, 32, 71, 67, 24, 73, 79, 38, 51, 77, 44, 85, 57, 40, 91, 83, 30, 89, 95, 46, 63, 97, 52, 101, 69, 50, 107, 103
Offset: 0

Views

Author

Philippe Deléham, May 01 2009

Keywords

Comments

Permutation of nonnegative integers.

Crossrefs

Formula

a(n)=lod_6(A000045(n)).

Extensions

Corrected by R. J. Mathar, May 02 2009

A160187 Lodumo_6 of Lucas numbers.

Original entry on oeis.org

2, 1, 3, 4, 7, 5, 0, 11, 17, 10, 9, 13, 16, 23, 15, 8, 29, 19, 6, 25, 31, 14, 21, 35, 20, 37, 27, 22, 43, 41, 12, 47, 53, 28, 33, 49, 34, 59, 39, 26, 65, 55, 18, 61, 67, 32, 45, 71, 38, 73, 51, 40, 79, 77, 24, 83, 89, 46, 57, 85, 52, 95, 63, 44, 101, 91, 30, 97, 103, 50, 69, 107
Offset: 0

Views

Author

Philippe Deléham, May 03 2009

Keywords

Comments

Permutation of nonnegative integers.

Crossrefs

Formula

a(n)=lod_6(A000032(n)).
Showing 1-9 of 9 results.