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 1-10 of 18 results. Next

A255529 Indices of primes in the 9th-order Fibonacci number sequence, A104144.

Original entry on oeis.org

10, 19, 878
Offset: 1

Views

Author

Robert Price, Feb 24 2015

Keywords

Comments

a(4) > 2*10^5.

Crossrefs

Programs

  • Mathematica
    a={0,0,0,0,0,0,0,0,1}; step=9; lst={}; For[n=step,n<=1000,n++, sum=Plus@@a; If[PrimeQ[sum], AppendTo[lst,n]]; a=RotateLeft[a]; a[[step]]=sum]; lst
  • PARI
    a104144(n) = polcoeff(x^8/(1-x-x^2-x^3-x^4-x^5-x^6-x^7-x^8-x^9) + O(x^(n+1)), n);
    lista(nn) = {for (n=1, nn, if (isprime(a104144(n)), print1(n, ", ")););} \\ Michel Marcus, Feb 27 2015

A122265 10th-order Fibonacci numbers: a(n+1) = a(n)+...+a(n-9) with a(0) = ... = a(8) = 0, a(9) = 1.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1023, 2045, 4088, 8172, 16336, 32656, 65280, 130496, 260864, 521472, 1042432, 2083841, 4165637, 8327186, 16646200, 33276064, 66519472, 132973664, 265816832, 531372800, 1062224128
Offset: 0

Views

Author

Roger L. Bagula and Gary W. Adamson, Oct 18 2006

Keywords

Comments

The (1,10)-entry of the matrix M^n, where M is the 10 X 10 matrix {{0,1,0,0,0, 0,0,0,0,0},{0,0,1,0,0,0,0,0,0,0},{0,0,0,1,0,0,0,0,0,0},{0,0,0,0,1,0,0,0,0,0}, {0,0,0,0,0,1,0,0,0,0},{0,0,0,0,0,0,1,0,0,0},{0,0,0,0,0,0,0,1,0,0},{0,0,0,0,0, 0,0,0,1,0},{0,0,0,0,0,0,0,0,0,1},{1,1,1,1,1,1,1,1,1,1}}.

Crossrefs

Cf. A257227, A257228 for primes in this sequence.

Programs

  • Maple
    with(linalg): p:=-1-x-x^2-x^3-x^4-x^5-x^6-x^7-x^8-x^9+x^10: M[1]:=transpose(companion(p,x)): for n from 2 to 40 do M[n]:=multiply(M[n-1],M[1]) od: seq(M[n][1,10],n=1..40);
    k:=10:for n from 0 to 50 do l(n):=sum((-1)^i*binomial(n-k+1-k*i,i)*2^(n-k+1-(k+1)*i),i=0..floor((n-k+1)/(k+1)))-sum((-1)^i*binomial(n-k-k*i,i)*2^(n-k-(k+1)*i),i=0..floor((n-k)/(k+1))):od:seq(l(n),n=0..50);k:=10:a:=taylor((z^(k-1)-z^(k))/(1-2*z+z^(k+1)),z=0,51);for p from 0 to 50 do j(p):=coeff(a,z,p):od :seq(j(p),p=0..50); # Richard Choulet, Feb 22 2010
  • Mathematica
    M = {{0, 1, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 1, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 1, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 1, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 1, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 1, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 1, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 1, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}}; v[1] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1}; v[n_] := v[n] = M.v[n - 1]; a = Table[Floor[v[n][[1]]], {n, 1, 50}]
    a={1,0,0,0,0,0,0,0,0,0};Flatten[Prepend[Table[s=Plus@@a;a=RotateLeft[a];a[[ -1]]=s,{n,60}],Table[0,{m,Length[a]-1}]]] (* Vladimir Joseph Stephan Orlovsky, Nov 18 2009 *)
    LinearRecurrence[{1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, 50]  (* Vladimir Joseph Stephan Orlovsky, May 25 2011 *)
    With[{nn=10},LinearRecurrence[Table[1,{nn}],Join[Table[0,{nn-1}],{1}],50]] (* Harvey P. Dale, Aug 17 2013 *)

Formula

a(n) = Sum_{j=1..10} a(n-j) for n>=10; a(n) = 0 for 0<=n<=8, a(9) = 1 (follows from the minimal polynomial of M; a Maple program based on this recurrence relation is much slower than the given Maple program, based on the definition).
G.f.: -x^9/(-1+x^10+x^9+x^8+x^7+x^6+x^5+x^4+x^3+x^2+x). - Maksym Voznyy (voznyy(AT)mail.ru), Jul 27 2009
Another form of the g.f. f: f(z)=(z^(k-1)-z^(k))/(1-2*z+z^(k+1)) with k=10. Then a(n)=sum((-1)^i*binomial(n-k+1-k*i,i)*2^(n-k+1-(k+1)*i),i=0..floor((n-k+1)/(k+1)))-sum((-1)^i*binomial(n-k-k*i,i)*2^(n-k-(k+1)*i),i=0..floor((n-k)/(k+1))) with k=10 and sum(alpha(i),i=m..n)=0 for m>n. - Richard Choulet, Feb 22 2010

Extensions

Edited by N. J. A. Sloane, Oct 29 2006 and Mar 05 2011

A251746 9-step Fibonacci sequence starting with 0,0,0,0,0,0,0,1,0.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 2, 4, 8, 16, 32, 64, 128, 255, 510, 1019, 2036, 4068, 8128, 16240, 32448, 64832, 129536, 258817, 517124, 1033229, 2064422, 4124776, 8241424, 16466608, 32900768, 65736704, 131343872, 262428927, 524340730, 1047648231, 2093232040
Offset: 0

Views

Author

Arie Bos, Dec 07 2014

Keywords

Comments

a(n+9) equals the number of n-length binary words avoiding runs of zeros of lengths 9i+8, (i=0,1,2,...). - Milan Janjic, Feb 26 2015

Crossrefs

Other 9-step Fibonacci sequences are A104144, A105755, A127193, A251747, A251748, A251749, A251750, A251751, A251752.
Cf. A255530 (Indices of primes in this sequence).

Programs

  • Mathematica
    LinearRecurrence[Table[1, {9}], {0, 0, 0, 0, 0, 0, 0, 1, 0}, 44] (* Michael De Vlieger, Dec 09 2014 *)

Formula

a(n+9) = a(n)+a(n+1)+a(n+2)+a(n+3)+a(n+4)+a(n+5)+a(n+6)+a(n+7)+a(n+8).
G.f.: x^7*(x-1)/(-1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9) . - R. J. Mathar, Mar 28 2025
a(n) = A104144(n+1)-A104144(n). - R. J. Mathar, Mar 28 2025

A251747 9-step Fibonacci sequence starting with 0,0,0,0,0,0,1,0,0.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 2, 4, 8, 16, 32, 64, 127, 254, 508, 1015, 2028, 4052, 8096, 16176, 32320, 64576, 129025, 257796, 515084, 1029153, 2056278, 4108504, 8208912, 16401648, 32770976, 65477376, 130825727, 261393658, 522272232, 1043515311, 2084974344
Offset: 0

Views

Author

Arie Bos, Dec 07 2014

Keywords

Crossrefs

Other 9-step Fibonacci sequences are A104144, A105755, A127193, A251746, A251748, A251749, A251750, A251751, A251752.
Cf. A255531 (Indices of primes in this sequence).

Programs

  • Mathematica
    LinearRecurrence[Table[1, {9}], {0, 0, 0, 0, 0, 0, 1, 0, 0}, 44] (* Michael De Vlieger, Dec 09 2014 *)

Formula

a(n+9) = a(n)+a(n+1)+a(n+2)+a(n+3)+a(n+4)+a(n+5)+a(n+6)+a(n+7)+a(n+8).
G.f.: x^6*(-1+x+x^2)/(-1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9) . - R. J. Mathar, Mar 28 2025
a(n) = A104144(n+2)-A104144(n+1)-A104144(n). - R. J. Mathar, Mar 28 2025

A251749 9-step Fibonacci sequence starting with 0,0,0,0,1,0,0,0,0.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 2, 4, 8, 16, 31, 62, 124, 248, 496, 991, 1980, 3956, 7904, 15792, 31553, 63044, 125964, 251680, 502864, 1004737, 2007494, 4011032, 8014160, 16012528, 31993503, 63923962, 127721960, 255192240, 509881616, 1018758495, 2035509496
Offset: 0

Views

Author

Arie Bos, Dec 07 2014

Keywords

Crossrefs

Other 9-step Fibonacci sequences are A104144, A105755, A127193, A251746, A251747, A251748, A251750, A251751, A251752.
Cf. A255532 (Indices of primes in this sequence).

Programs

  • Mathematica
    LinearRecurrence[Table[1, {9}], {0, 0, 0, 0, 1, 0, 0, 0, 0}, 44] (* Michael De Vlieger, Dec 09 2014 *)

Formula

a(n+9) = a(n)+a(n+1)+a(n+2)+a(n+3)+a(n+4)+a(n+5)+a(n+6)+a(n+7)+a(n+8).
G.f.: x^4*(-1+x+x^2+x^3+x^4)/(-1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9) . - R. J. Mathar, Mar 28 2025

A251750 9-step Fibonacci sequence starting with 0,0,0,1,0,0,0,0,0.

Original entry on oeis.org

0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 2, 4, 8, 15, 30, 60, 120, 240, 480, 959, 1916, 3828, 7648, 15281, 30532, 61004, 121888, 243536, 486592, 972225, 1942534, 3881240, 7754832, 15494383, 30958234, 61855464, 123589040, 246934544, 493382496, 985792767, 1969643000
Offset: 0

Views

Author

Arie Bos, Dec 07 2014

Keywords

Crossrefs

Other 9-step Fibonacci sequences are A104144, A105755, A127193, A251746, A251747, A251748, A251749, A251751, A251752.
Cf. A255533 (Indices of primes in this sequence).

Programs

  • Mathematica
    LinearRecurrence[Table[1, {9}], {0, 0, 0, 1, 0, 0, 0, 0, 0}, 44] (* Michael De Vlieger, Dec 09 2014 *)

Formula

a(n+9) = a(n)+a(n+1)+a(n+2)+a(n+3)+a(n+4)+a(n+5)+a(n+6)+a(n+7)+a(n+8).
G.f.: x^3*(-1+x+x^2+x^3+x^4+x^5)/(-1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9) . - R. J. Mathar, Mar 28 2025

A251751 9-step Fibonacci sequence starting with 0,0,1,0,0,0,0,0,0.

Original entry on oeis.org

0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 2, 4, 7, 14, 28, 56, 112, 224, 448, 895, 1788, 3572, 7137, 14260, 28492, 56928, 113744, 227264, 454080, 907265, 1812742, 3621912, 7236687, 14459114, 28889736, 57722544, 115331344, 230435424, 460416768, 919926271, 1838039800
Offset: 0

Views

Author

Arie Bos, Dec 07 2014

Keywords

Crossrefs

Other 9-step Fibonacci sequences are A104144, A105755, A127193, A251746, A251747, A251748, A251749, A251750, A251752.
Cf. A255534 (Indices of primes in this sequence).

Programs

  • Mathematica
    LinearRecurrence[Table[1, {9}], {0, 0, 1, 0, 0, 0, 0, 0, 0}, 44] (* Michael De Vlieger, Dec 09 2014 *)

Formula

a(n+9) = a(n)+a(n+1)+a(n+2)+a(n+3)+a(n+4)+a(n+5)+a(n+6)+a(n+7)+a(n+8).
G.f.: x^2*(-1+x+x^2+x^3+x^4+x^5+x^6)/(-1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9) . - R. J. Mathar, Mar 28 2025
a(n) = A172319(n-2)-2*A172319(n-3)+A172319(n-9). - R. J. Mathar, Mar 28 2025

A251752 9-step Fibonacci sequence starting with 0,1,0,0,0,0,0,0,0.

Original entry on oeis.org

0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 6, 12, 24, 48, 96, 192, 384, 767, 1532, 3061, 6116, 12220, 24416, 48784, 97472, 194752, 389120, 777473, 1553414, 3103767, 6201418, 12390616, 24756816, 49464848, 98832224, 197469696, 394550272, 788323071, 1575092728
Offset: 0

Views

Author

Arie Bos, Dec 07 2014

Keywords

Crossrefs

Other 9-step Fibonacci sequences are A104144, A105755, A127193, A251746, A251747, A251748, A251749, A251750, A251751.
Cf. A255536 (Indices of primes in this sequence).

Programs

  • Mathematica
    LinearRecurrence[Table[1, {9}], {0, 1, 0, 0, 0, 0, 0, 0, 0}, 44] (* Michael De Vlieger, Dec 09 2014 *)

Formula

a(n+9) = a(n)+a(n+1)+a(n+2)+a(n+3)+a(n+4)+a(n+5)+a(n+6)+a(n+7)+a(n+8).
G.f.: x*(-1+x+x^2+x^3+x^4+x^5+x^6+x^7)/(-1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9) . - R. J. Mathar, Mar 28 2025
a(n) = A172319(n-1)-2*A172319(n-2)+A172319(n-9). - R. J. Mathar, Mar 28 2025

A105753 Lexicographically earliest sequence of positive integers with the property that a(a(n)) = a(1)+a(2)+...+a(n).

Original entry on oeis.org

1, 3, 4, 8, 6, 22, 9, 16, 53, 11, 133, 13, 279, 15, 573, 69, 18, 1233, 20, 2486, 23, 44, 4995, 25, 10059, 27, 20145, 29, 40319, 31, 80669, 33, 161371, 35, 322777, 37, 645591, 39, 1291221, 41, 2582483, 43, 5165009, 5039, 46, 10335103, 48
Offset: 1

Views

Author

Eric Angelini, Aug 13 2006

Keywords

Comments

The Fibonacci 9-step numbers referenced in the Noe-Post paper are in A104144. - T. D. Noe, Oct 27 2008

Examples

			Sequence reads from the beginning:
- at position a(1)=1 we see the sum of all previously written terms [indeed, nil + 1=1]
- at position a(2)=3 we see the sum of all previously written terms [indeed, 1+ 3=4]
- at position a(3)=4 we see the sum of all previously written terms [indeed, 1+3+4=8]
- at position a(4)=8 we see the sum of all previously written terms [indeed, 1+3+4+8=16]
- at position a(5)=6 we see the sum of all previously written terms [indeed, 1+3+4+8+6=22]
- at position a(6)=22 we see the sum of all previously written terms [indeed, 1+3+4+8+6+22=44 and 44 is the 22nd term of S]
etc.
		

Crossrefs

Extensions

More terms from Max Alekseyev, Aug 14 2006
Edited by Max Alekseyev, Mar 08 2015

A251748 9-step Fibonacci sequence starting with 0,0,0,0,0,1,0,0,0.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 2, 4, 8, 16, 32, 63, 126, 252, 504, 1007, 2012, 4020, 8032, 16048, 32064, 64065, 128004, 255756, 511008, 1021009, 2040006, 4075992, 8143952, 16271856, 32511648, 64959231, 129790458, 259325160, 518139312, 1035257615, 2068475224
Offset: 0

Views

Author

Arie Bos, Dec 07 2014

Keywords

Comments

The only primes in this sequence whose indices are less than 2*10^5 are 2 and 65865769729, which correspond to indices of 10 and 45. - Robert Price, Feb 24 2015

Crossrefs

Other 9-step Fibonacci sequences are A104144, A105755, A127193, A251746, A251747, A251749, A251750, A251751, A251752.

Programs

  • Mathematica
    LinearRecurrence[Table[1, {9}], {0, 0, 0, 0, 0, 1, 0, 0, 0}, 44] (* Michael De Vlieger, Dec 09 2014 *)

Formula

a(n+9) = a(n)+a(n+1)+a(n+2)+a(n+3)+a(n+4)+a(n+5)+a(n+6)+a(n+7)+a(n+8).
G.f.: x^5*(-1+x+x^2+x^3)/(-1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9) . - R. J. Mathar, Mar 28 2025
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