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.

Previous Showing 21-30 of 36 results. Next

A254412 Indices of primes in the 8th-order Fibonacci number sequence, A123526.

Original entry on oeis.org

11, 13, 15, 24, 30, 33, 57, 104, 121, 132, 149, 158, 178, 220, 295, 389, 1070, 1101, 1373, 1761, 1778, 2333, 2731, 4541, 5189, 5237, 5738, 8025, 8787, 10561, 11783, 13435, 14638, 15337, 20985, 21722, 24770, 31009, 57367, 65877, 129773, 134630, 167020
Offset: 1

Views

Author

Robert Price, Jan 30 2015

Keywords

Comments

a(44) > 2*10^5.

Links

Crossrefs

Cf. A001590, A001631, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523, A214825, A235862, A000288, A000322, A000383, A249413, A060455, A079262, A123526, A254413.

Programs

  • Mathematica
    a={1,1,1,1,1,1,1,1}; step=8; lst={}; For[n=step+1,n<=1000,n++, sum=Plus@@a; If[PrimeQ[sum], AppendTo[lst,n]]; a=RotateLeft[a]; a[[step]]=sum]; lst

A104187 Expansion of g.f. -(1+x^2+x^4)/((x^3+x^2+x-1)*(x-1)^2).

Original entry on oeis.org

1, 3, 8, 18, 38, 76, 147, 279, 523, 973, 1802, 3328, 6136, 11302, 20805, 38285, 70437, 129575, 238348, 438414, 806394, 1483216, 2728087, 5017763, 9229135, 16975057, 31222030
Offset: 0

Views

Author

Creighton Dement, Apr 01 2005

Keywords

Comments

A floretion-generated sequence involving tribonacci numbers.
Floretion Algebra Multiplication Program, FAMP Code: 1tesforrokseq[A*B] = A = - .5'ii' + .5'jj' + .5'kk' + .5e B = + 'kj', 1vesforrokseq[A*B] = A000004, ForType: 1A.

Links

Crossrefs

Cf. A081172.

Programs

  • Mathematica
    CoefficientList[Series[-(1+x^2+x^4)/((x^3+x^2+x-1)*(x-1)^2), {x,0,30}], x] (* or *) LinearRecurrence[{3,-2,0,-1,1},{1,3,8,18,38},30] (* Harvey P. Dale, Jun 14 2011 *)

Formula

a(n+2) - 2*a(n+1) + a(n) = A081172(n+4).
a(n) = (1/2) [A000073(n+3) + A000073(n+6) - 3n - 6 ]. - Ralf Stephan, May 20 2007
a(0)=1, a(1)=3, a(2)=8, a(3)=18, a(4)=38, a(n) = 3*a(n-1) - 2*a(n-2) - a(n-4) + a(n-5). - Harvey P. Dale, Jun 14 2011

Extensions

Definition corrected by Harvey P. Dale, Jun 14 2011

A202012 Expansion of (1-x+x^2)/((1-x)(1-x-x^2-x^3)).

Original entry on oeis.org

1, 1, 3, 6, 11, 21, 39, 72, 133, 245, 451, 830, 1527, 2809, 5167, 9504, 17481, 32153, 59139, 108774, 200067, 367981, 676823, 1244872, 2289677, 4211373, 7745923, 14246974, 26204271, 48197169, 88648415, 163049856
Offset: 0

Views

Author

Philippe Deléham, Dec 08 2011

Keywords

Comments

Antidiagonal sums of triangle T(n,k) = A104040(n,k)*(-1)^floor(k/2). - Philippe Deléham, Dec 11 2011

Links

Crossrefs

Cf. A008937, A081172, A104040.

Programs

  • Mathematica
    CoefficientList[Series[(1-x+x^2)/((1-x)(1-x-x^2-x^3)),{x,0,40}],x] (* or *) LinearRecurrence[{2,0,0,-1},{1,1,3,6},40] (* Harvey P. Dale, Apr 21 2014 *)

Formula

a(n) = 2*a(n-1) - a(n-4), n>3.
a(n) = A008937(n-1) - A008937(n) + A008937(n+1). - R. J. Mathar, Dec 10 2011
a(n+1)-a(n) = A081172(n+2). - Philippe Deléham, Dec 11 2011

A242315 Indices of primes in the tribonacci-like sequence A214826.

Original entry on oeis.org

4, 7, 23, 71, 379, 467, 596, 6372, 10100, 11660, 23099, 25419, 26011, 36588, 76895, 112867
Offset: 1

Views

Author

Robert Price, May 10 2014

Keywords

Comments

a(17) > 2*10^5.

Links

Crossrefs

Cf. A001590, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523,A214825, A235862, A214826.

Programs

  • Mathematica
    a={1,4,4}; For[n=3, n<=1000, n++, sum=Plus@@a; If[PrimeQ[sum], Print[n]]; a=RotateLeft[a]; a[[3]]=sum]

A244930 Indices of primes in A214831.

Original entry on oeis.org

3, 4, 7, 8, 16, 26, 34, 42, 78, 94, 101, 107, 216, 255, 543, 562, 851, 981, 1099, 1528, 1824, 1955, 2122, 2488, 2500, 15331, 15961, 24107, 24938, 26051, 58504, 61617, 81034, 85119, 89768, 90597, 97191, 116899, 195346
Offset: 1

Views

Author

Robert Price, Jul 08 2014

Keywords

Comments

a(40) > 2*10^5.

Links

Crossrefs

Cf. A001590, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523, A214825, A235862, A214827, A214828, A214829, A243622, A243623, A214831.

Programs

A248700 Indices of primes in the Heptanacci numbers sequence A122189.

Original entry on oeis.org

8, 14, 22, 102495, 130447, 173590
Offset: 1

Views

Author

Robert Price, Dec 02 2014

Keywords

Comments

a(7) > 2*10^5.

Links

Crossrefs

Cf. A001590, A001631, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523, A214825, A235862, A000288, A000322, A122189.

Programs

  • Mathematica
    a={0,0,0,0,0,0,1}; For[n=7, n<=1000, n++, sum=Plus@@a; If[PrimeQ[sum], Print[n]]; a=RotateLeft[a]; a[[7]]=sum]

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.

Links

Crossrefs

Cf. A001590, A001631, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523, A214825, A235862, A000288, A000322, A000383, A249413, A060455, A079262, A104144.

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

A255530 Indices of primes in the 9th-order Fibonacci number sequence, A251746.

Original entry on oeis.org

10, 19, 59, 79, 12487
Offset: 1

Views

Author

Robert Price, Feb 24 2015

Keywords

Comments

a(6) > 2*10^5.

Links

Crossrefs

Cf. A001590, A001631, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523, A214825, A235862, A000288, A000322, A000383, A249413, A060455, A079262, A251746.

Programs

  • Mathematica
    a={0,0,0,0,0,0,0,1,0}; 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

A255531 Indices of primes in the 9th-order Fibonacci number sequence, A251747.

Original entry on oeis.org

10, 16, 116, 236, 316, 1376, 5066, 103696, 120949
Offset: 1

Views

Author

Robert Price, Feb 24 2015

Keywords

Comments

a(10) > 2*10^5.

Links

Crossrefs

Cf. A001590, A001631, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523, A214825, A235862, A000288, A000322, A000383, A249413, A060455, A079262, A251747.

Programs

  • Mathematica
    a={0,0,0,0,0,0,1,0,0}; 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
Flatten[Position[LinearRecurrence[Table[1,{9}],{0,0,0,0,0,0,1,0,0},125000],?PrimeQ]]-1 (* _Harvey P. Dale, Nov 29 2017 *)

A255532 Indices of primes in the 9th-order Fibonacci number sequence, A251749.

Original entry on oeis.org

10, 14, 19, 29, 404, 1744, 8854, 27754
Offset: 1

Views

Author

Robert Price, Feb 24 2015

Keywords

Comments

a(9) > 2*10^5.

Links

Crossrefs

Cf. A001590, A001631, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523, A214825, A235862, A000288, A000322, A000383, A249413, A060455, A079262, A251749.

Programs

  • Mathematica
    a={0,0,0,0,1,0,0,0,0}; 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
Previous Showing 21-30 of 36 results. Next

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