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 11-19 of 19 results.

A254367 a(n) = 5*2^(n+2) + 2^(2n+2) + 10*3^n + 5^n + 35.

Original entry on oeis.org

70, 126, 294, 846, 2814, 10326, 40614, 168126, 723534, 3208806, 14570934, 67417806, 316645854, 1505245686, 7225414854, 34956689886, 170199537774, 832952952966, 4093454620374, 20184631056366, 99800366967294, 494533989722646, 2454868429675494
Offset: 0

Views

Author

Luciano Ancora, Jan 30 2015

Keywords

Comments

This is the sequence of fifth terms of "fourth partial sums of m-th powers".

Crossrefs

Programs

  • Magma
    [5*2^(n+2)+2^(2*n+2)+10*3^n+5^n+35: n in [0..30]]; // Vincenzo Librandi, Feb 02 2015
  • Mathematica
    Table[5 2^(n + 2) + 2^(2 n + 2) + 10 3^n + 5^n + 35, {n, 0, 30}] (* Vincenzo Librandi, Feb 02 2015 *)
  • PARI
    vector(30, n, n--; 5*2^(n+2) + 2^(2*n+2) + 10*3^n + 5^n + 35) \\ Colin Barker, Jan 30 2015
    

Formula

a(n) = 15*a(n-1)-85*a(n-2)+225*a(n-3)-274*a(n-4)+120*a(n-5). - Colin Barker, Jan 30 2015
G.f.: -2*(2972*x^4-4302*x^3+2177*x^2-462*x+35) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)). - Colin Barker, Jan 30 2015

A242475 a(n) = 2^n + 8.

Original entry on oeis.org

9, 10, 12, 16, 24, 40, 72, 136, 264, 520, 1032, 2056, 4104, 8200, 16392, 32776, 65544, 131080, 262152, 524296, 1048584, 2097160, 4194312, 8388616, 16777224, 33554440, 67108872, 134217736, 268435464, 536870920, 1073741832
Offset: 0

Views

Author

Vincenzo Librandi, May 20 2014

Keywords

Crossrefs

Programs

  • Magma
    [2^n+8: n in [0..40]];
  • Mathematica
    Table[2^n + 8, {n, 0, 40}] (* or *) CoefficientList[Series[(9 - 17 x)/((1 - x) (1 - 2 x)),{x, 0, 30}], x]
    LinearRecurrence[{3,-2},{9,10},40] (* Harvey P. Dale, May 21 2025 *)

Formula

G.f.: (9 - 17*x)/((1 - x)*(1 - 2*x)).
a(n) = 2*a(n-1) - 8 = 3*a(n-1) - 2*a(n-2).
a(n) = A052548(n)+6 = A140504(n)+4 = A153972(n)+2.
E.g.f.: exp(2*x) + 8*exp(x). - Elmo R. Oliveira, Nov 11 2023

A246139 a(n) = 2^n + 10.

Original entry on oeis.org

11, 12, 14, 18, 26, 42, 74, 138, 266, 522, 1034, 2058, 4106, 8202, 16394, 32778, 65546, 131082, 262154, 524298, 1048586, 2097162, 4194314, 8388618, 16777226, 33554442, 67108874, 134217738, 268435466, 536870922, 1073741834, 2147483658, 4294967306
Offset: 0

Views

Author

Vincenzo Librandi, Aug 18 2014

Keywords

Comments

First trisection of A085688. [Bruno Berselli, Aug 19 2014]

Crossrefs

Cf. Sequences of the form 2^n + k: A000079 (k=0), A000051 (k=1), A052548 (k=2), A062709 (k=3), A140504 (k=4), A168614 (k=5), A153972 (k=6), A168415 (k=7), A242475 (k=8), A188165 (k=9), this sequence (k=10).
Cf. A085688.

Programs

  • Magma
    [2^n+10: n in [0..40]];
    
  • Mathematica
    Table[2^n + 10, {n, 0, 40}]
  • PARI
    vector(50, n, 2^(n-1)+10) \\ Derek Orr, Aug 18 2014

Formula

G.f.: (11 - 21*x)/(1 - 3*x + 2*x^2).
a(n) = A000079(n) + 10.
a(n) = 3*a(n-1) - 2*a(n-2) for n > 1.
E.g.f.: exp(2*x) + 10*exp(x). - Elmo R. Oliveira, Nov 11 2023

A140505 Second differences of Jacobsthal sequence A001045, pairs with even and odd indices swapped.

Original entry on oeis.org

2, -1, 4, 0, 12, 4, 44, 20, 172, 84, 684, 340, 2732, 1364, 10924, 5460, 43692, 21844, 174764, 87380, 699052, 349524, 2796204, 1398100, 11184812, 5592404, 44739244, 22369620, 178956972, 89478484, 715827884, 357913940, 2863311532, 1431655764, 11453246124
Offset: 0

Views

Author

Paul Curtz, Jun 30 2008

Keywords

Comments

The second differences are -1, 2, 0, 4, 4, 12, 20, 44, ... (-1)^(n+1)*A084247(n), essentially A097073, which are listed here with -1 <=> 2, 0 <=> 4 etc. swapped in pairs.

Formula

a(n) = 4*A092808(n-2), n>1.
a(n+1) - 2a(n) = (-1)^n*A140504(n).
O.g.f.: (2+x-5x^2)/[(1+x)(1-2x)(1+2x)]. - R. J. Mathar, Jul 08 2008

Extensions

Edited by R. J. Mathar, Jul 08 2008

A254465 a(n) = 35*2^n + 10*4^n + 20*3^n + 4*5^n + 6^n + 56.

Original entry on oeis.org

126, 252, 672, 2232, 8592, 36552, 166992, 804552, 4037712, 20923272, 111231312, 603667272, 3331889232, 18646768392, 105558814032, 603280840392, 3475274371152, 20152803339912, 117513698083152, 688425727971912, 4048693055291472, 23888489018765832, 141334996634766672, 838119509472869832
Offset: 0

Views

Author

Luciano Ancora, Jan 31 2015

Keywords

Comments

This is the sequence of sixth terms of "fourth partial sums of m-th powers".

Crossrefs

Programs

  • Mathematica
    Table[35 2^n + 10 4^n + 20 3^n + 4 5^n + 6^n + 56, {n, 0, 24}] (* Michael De Vlieger, Jan 31 2015 *)
    LinearRecurrence[{21,-175,735,-1624,1764,-720},{126,252,672,2232,8592,36552},30] (* Harvey P. Dale, Aug 02 2024 *)
  • PARI
    vector(30, n, n--; 35*2^n + 10*4^n + 20*3^n + 4*5^n + 6^n + 56) \\ Colin Barker, Jan 31 2015

Formula

G.f.: -6*(10036*x^5 -16454*x^4 +10065*x^3 -2905*x^2 +399*x -21) / ((x -1)*(2*x -1)*(3*x -1)*(4*x -1)*(5*x -1)*(6*x -1)). - Colin Barker, Jan 31 2015
a(n) = 21*a(n-1)-175*a(n-2)+735*a(n-3)-1624*a(n-4)+1764*a(n-5)-720*a(n-6). - Colin Barker, Jan 31 2015

A254466 a(n) = 56*2^n + 20*4^n + 35*3^n + 4*6^n + 10*5^n + 7^n + 84.

Original entry on oeis.org

210, 462, 1386, 5214, 22770, 110022, 571626, 3136014, 17944290, 106156182, 645091866, 4006997214, 25344197010, 162737255142, 1058251916106, 6955456112814, 46130658756930, 308314670926902, 2074188361172346, 14032607275346814, 95392686703000050
Offset: 0

Views

Author

Luciano Ancora, Jan 31 2015

Keywords

Comments

This is the sequence of seventh terms of "fourth partial sums of m-th powers".

Crossrefs

Programs

  • Mathematica
    Table[56 2^n + 20 4^n + 35 3^n + 4 6^n + 10 5^n + 7^n + 84, {n, 0, 24}] (* Michael De Vlieger, Jan 31 2015 *)
  • PARI
    vector(30, n, n--; 56*2^n + 20*4^n + 35*3^n + 4*6^n + 10*5^n + 7^n + 84) \\ Colin Barker, Jan 31 2015

Formula

G.f.: -6*(110440*x^6 -199272*x^5 +139840*x^4 -49405*x^3 +9345*x^2 -903*x +35) / ((x -1)*(2*x -1)*(3*x -1)*(4*x -1)*(5*x -1)*(6*x -1)*(7*x -1)). - Colin Barker, Jan 31 2015
a(n) = 28*a(n-1) -322*a(n-2) +1960*a(n-3) -6769*a(n-4) +13132*a(n-5) -13068*a(n-6) +5040*a(n-7). - Colin Barker, Jan 31 2015

A295077 a(n) = 2*n*(n-1) + 2^n - 1.

Original entry on oeis.org

0, 1, 7, 19, 39, 71, 123, 211, 367, 655, 1203, 2267, 4359, 8503, 16747, 33187, 66015, 131615, 262755, 524971, 1049335, 2097991, 4195227, 8389619, 16778319, 33555631, 67110163, 134219131, 268436967, 536872535, 1073743563, 2147485507
Offset: 0

Views

Author

Keywords

Comments

We have a(0) = 0, and for n > 0, a(n) is a subsequence of A131098 where the indices are given by the partial sums of A288382.
For n > 0, a(n) gives the number of words of length n over the alphabet A = {a,b,c,d} such that: a word containing 'c' does not contain 'b' or 'd'; a word cannot be fully written with 'a'; a word contains letters from {b,d} if and only if it contains exactly a unique couple of letters from {b,d}. Thus a(1) = 1 where the corresponding word is "c" since 'c' is the only letter allowed to be written alone.
Primes in the sequence are 7, 19, 71, 211, 367, 2267, 16747, 524971, ... which are of the form 4*k + 3 (A002145).
The second difference of this sequence is A140504.

Examples

			a(4) = 39. The corresponding words are aabb, aabd, aadb, aadd, abab, abad, abba, abda, adab, adad, adba, adda, aaac, aaca, aacc, acaa, acac, acca, accc, baab, baad, baba, bada, bbaa, bdaa, caaa, caac, caca, cacc, ccaa, ccac, ccca, cccc, daab, daad, daba, dada, dbaa, ddaa.
		

References

  • R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics: A Foundation for Computer Science, Addison-Wesley, 1994.

Crossrefs

Programs

  • Magma
    [2*n*(n-1)+2^n-1 : n in [0..40]]; // Wesley Ivan Hurt, Nov 26 2017
  • Maple
    A295077:=n->2*n*(n-1)+2^n-1; seq(A295077(n), n=0..70);
  • Mathematica
    Table[2 n (n - 1) + 2^n - 1, {n, 0, 70}]
  • PARI
    a(n) = 2*n*(n-1) + 2^n - 1; \\ Michel Marcus, Nov 14 2017
    

Formula

G.f.: (x + 2*x^2 - 7*x^3)/((1 - x)^3*(1 - 2*x)).
a(0)=0, a(1)=1, a(2)=7, a(3)=19; for n>3, a(n) = 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - 2*a(n-4).
a(n) = 2*A131924(n-1) - 1 for n>0, a(0)=0.
a(n) = a(n-1) + A000079(n-1) + A008586(n-1) for n>0, a(0)=0.
a(n) = A126646(n-1) + A046092(n-1) for n>0, a(0)=0.
a(n+1) - 2*a(n) + a(n-1) = A140504(n-1) for n>0, a(0)=0.
E.g.f.: exp(2*x) - (1 - 2*x^2)*exp(x). - G. C. Greubel, Oct 17 2018

A146528 a(0) = 4; for n >= 1, a(n) = 2^n + 4.

Original entry on oeis.org

4, 6, 8, 12, 20, 36, 68, 132, 260, 516, 1028, 2052, 4100, 8196, 16388, 32772, 65540, 131076, 262148, 524292, 1048580, 2097156, 4194308, 8388612, 16777220, 33554436, 67108868, 134217732, 268435460, 536870916, 1073741828
Offset: 0

Views

Author

Roger L. Bagula, Oct 30 2008

Keywords

Comments

This is one of many possible ways to extend the Platonic solids sequence A053016.

Crossrefs

Essentially the same as A140504.

Programs

  • Mathematica
    v[n_] := 2*(If[n == 0, 0, 2^(n - 1)] + 2); Table[v[n], {n, 0, 30}]

Formula

a(n)=A140504(n), n>0. [From R. J. Mathar, Nov 05 2008]

Extensions

Edited by N. J. A. Sloane, Mar 21 2021

A267615 a(n) = 2^n + 11.

Original entry on oeis.org

12, 13, 15, 19, 27, 43, 75, 139, 267, 523, 1035, 2059, 4107, 8203, 16395, 32779, 65547, 131083, 262155, 524299, 1048587, 2097163, 4194315, 8388619, 16777227, 33554443, 67108875, 134217739, 268435467, 536870923, 1073741835, 2147483659, 4294967307, 8589934603, 17179869195, 34359738379
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 18 2016

Keywords

Comments

Recurrence relation b(n) = 3*b(n - 1) - 2*b(n - 2) for n>1, b(0) = k, b(1) = k + 1, gives the closed form b(n) = 2^n + k - 1.

Crossrefs

Cf. sequences with closed form 2^n + k - 1: A168616 (k=-4), A028399 (k=-3), A036563 (k=-2), A000918 (k=-1), A000225 (k=0), A000079 (k=1), A000051 (k=2), A052548 (k=3), A062709 (k=4), A140504 (k=5), A168614 (k=6), A153972 (k=7), A168415 (k=8), A242475 (k=9), A188165 (k=10), A246139 (k=11), this sequence (k=12).
Cf. A156940.

Programs

  • Magma
    [2^n+11: n in [0..30]]; // Vincenzo Librandi, Jan 19 2016
  • Mathematica
    Table[2^n + 11, {n, 0, 35}]
    LinearRecurrence[{3, -2}, {12, 13}, 40] (* Vincenzo Librandi, Jan 19 2016 *)
  • PARI
    a(n) = 2^n + 11; \\ Altug Alkan, Jan 18 2016
    

Formula

G.f.: (12 - 23*x)/(1 - 3*x + 2*x^2).
a(n) = 3*a(n - 1) - 2*a(n - 2) for n>1, a(0)=12, a(1)=13.
a(n) = A000079(n) + A010850(n).
Sum_{n>=0} 1/a(n) = 0.367971714327125...
Lim_{n->oo} a(n + 1)/a(n) = 2.
E.g.f.: exp(2*x) + 11*exp(x). - Elmo R. Oliveira, Nov 08 2023
Previous Showing 11-19 of 19 results.