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.

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A175162 a(n) = 16*(2^n + 1).

Original entry on oeis.org

32, 48, 80, 144, 272, 528, 1040, 2064, 4112, 8208, 16400, 32784, 65552, 131088, 262160, 524304, 1048592, 2097168, 4194320, 8388624, 16777232, 33554448, 67108880, 134217744, 268435472, 536870928, 1073741840, 2147483664, 4294967312, 8589934608, 17179869200
Offset: 0

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Author

Reinhard Zumkeller, Feb 28 2010

Keywords

Crossrefs

Sequences of the form m*(2^n + 1): A000051 (m=1), A052548 (m=2), A140504 (m=4), A153973 (m=6), A231643 (m=5), A175161 (m=8), this sequence (m=16), A175163 (m=32).
Cf. A173786.

Programs

  • Magma
    I:=[32,48]; [n le 2 select I[n] else 3*Self(n-1) - 2*Self(n-2): n in [1..41]]; // G. C. Greubel, Jul 08 2021
    
  • Mathematica
    16*(2^Range[0,30] +1) (* or *) LinearRecurrence[{3,-2},{32,48},30] (* Harvey P. Dale, Jun 08 2017 *)
  • Sage
    [16*(2^n +1) for n in (0..40)] # G. C. Greubel, Jul 08 2021

Formula

a(n) = A173786(n+4, 4).
a(n) = 3*a(n-1) - 2*a(n-2), a(0)=32, a(1)=48. - Vincenzo Librandi, Dec 28 2010
From G. C. Greubel, Jul 08 2021: (Start)
G.f.: 16*(2 - 3*x)/((1-x)*(1-2*x)).
E.g.f.: 16*(exp(2*x) + exp(x)). (End)

A175163 a(n) = 32*(2^n + 1).

Original entry on oeis.org

64, 96, 160, 288, 544, 1056, 2080, 4128, 8224, 16416, 32800, 65568, 131104, 262176, 524320, 1048608, 2097184, 4194336, 8388640, 16777248, 33554464, 67108896, 134217760, 268435488, 536870944
Offset: 0

Views

Author

Reinhard Zumkeller, Feb 28 2010

Keywords

Crossrefs

Sequences of the form m*(2^n + 1): A000051 (m=0), A052548 (m=2), A140504 (m=4), A153973 (m=6), A231643 (m=5), A175161 (m=8), A175162 (m=16), this sequence (m=32).
Cf. A173786.

Programs

  • Magma
    I:=[64,96]; [n le 2 select I[n] else 3*Self(n-1) - 2*Self(n-2): n in [1..41]]; // G. C. Greubel, Jul 08 2021
    
  • Mathematica
    32*(2^Range[0,40] + 1) (* G. C. Greubel, Jul 08 2021 *)
  • Sage
    [32*(2^n +1) for n in (0..40)] # G. C. Greubel, Jul 08 2021

Formula

a(n) = A173786(n+5, 5).
a(n) = 3*a(n-1) - 2*a(n-2), a(0)=64, a(1)=96. - Vincenzo Librandi, Dec 28 2010
G.f.: 32*(2 - 3*x)/((1 - x)*(1 - 2*x)). - Chai Wah Wu, Jul 24 2020
E.g.f.: 32*(exp(2*x) + exp(x)). - G. C. Greubel, Jul 08 2021

A346303 Positions of words in A076478 that start with 0 and end with 0.

Original entry on oeis.org

1, 3, 7, 9, 15, 17, 19, 21, 31, 33, 35, 37, 39, 41, 43, 45, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179
Offset: 1

Views

Author

Clark Kimberling, Jul 21 2021

Keywords

Comments

The sequences A346303, A171757, A346304, A346305 partition the positive integers. See A076478 for a guide to related sequences.
The position of the words 0, 00, 000, 0000, ... (all-zero) in A076478 is given by A000225. So this sequence is given by the subsequence A000225 and filling the gaps halfway up (until the leading 0 toggles) with odd numbers, from 7 to 9, from 15 to 21, from 31 to 45 etc. So the first differences are 2, 4, 2, 6, 2, 2, 2, 10, 2, 2, 2, 2, 2, 2, 2, 18, 2, 2, ... which is A052548 with 1, 3, 7, 15,... (A000225) intermediate 2's. - R. J. Mathar, Sep 08 2021

Examples

			The first fourteen words w(n) are 0, 1, 00, 01, 10, 11, 000, 001, 010, 011, 100, 101, 110, 111, so that a(3) = 7.
		

Crossrefs

Programs

A132753 a(n) = 2^(n+1) - n + 1.

Original entry on oeis.org

3, 4, 7, 14, 29, 60, 123, 250, 505, 1016, 2039, 4086, 8181, 16372, 32755, 65522, 131057, 262128, 524271, 1048558, 2097133, 4194284, 8388587, 16777194, 33554409, 67108840, 134217703, 268435430, 536870885, 1073741796, 2147483619
Offset: 0

Views

Author

Gary W. Adamson, Aug 28 2007

Keywords

Comments

Apart from a(0): Row sums of triangle A132752 (old name).
Apart from a(0): Binomial transform of [1, 3, 0, 4, 0, 4, 0, 4, ...].

Examples

			a(3) = 14 = sum of row 3 terms of triangle A132752: (3 + 5 + 5 + 1).
a(3) = 14 = (1, 3, 3, 1) dot (1, 3, 0, 4) = (1 + 9 + 0 + 4).
		

Crossrefs

Programs

  • Magma
    [2^(n+1) -n+1: n in [0..40]]; // G. C. Greubel, Feb 16 2021
  • Maple
    A132753:= n-> 2^(n+1) -n+1; seq(A132753(n), n=0..40) # G. C. Greubel, Feb 16 2021
  • Mathematica
    Table[2^(n+1) -n+1, {n, 0, 30}] (* Bruno Berselli, Aug 31 2013 *)
  • PARI
    a(n)=2^(n+1)-n+1
    
  • PARI
    Vec( (3-8*x+6*x^2)/((1-x)^2*(1-2*x)) + O(x^40)) \\ Colin Barker, Mar 14 2014
    
  • Sage
    [2^(n+1) -n+1 for n in (0..40)] # G. C. Greubel, Feb 16 2021
    

Formula

From Colin Barker, Mar 14 2014: (Start)
a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3).
G.f.: (3 - 8*x + 6*x^2)/((1-x)^2 * (1-2*x)). (End)
E.g.f.: (1-x)*exp(x) + 2*exp(2*x). - G. C. Greubel, Feb 16 2021

Extensions

More terms Vladimir Joseph Stephan Orlovsky, Dec 25 2008
Changed first member, and better name from Ralf Stephan, Aug 31 2013

A191488 A companion to Gould’s sequence A001316.

Original entry on oeis.org

4, 6, 8, 10, 8, 12, 16, 18, 8, 12, 16, 20, 16, 24, 32, 34, 8, 12, 16, 20, 16, 24, 32, 36, 16, 24, 32, 40, 32, 48, 64, 66, 8, 12, 16, 20, 16, 24, 32, 36, 16, 24, 32, 40, 32, 48, 64, 68, 16, 24, 32, 40, 32, 48, 64, 72, 32, 48, 64, 80, 64, 96, 128
Offset: 0

Views

Author

Johannes W. Meijer, Jun 05 2011

Keywords

Comments

The row sums of the Sierpinski-Stern triangle A191372 are given by sequence A191487.
The differences diff1(n) = A191487(2*n+3) - A191487(2*n+1) lead to a peculiar number triangle, see the examples. The leading terms of the rows of the diff1(n) triangle clearly stand out from the rest of the terms and are given by A001550(p+1), p>=1; for p=0 this term is 7.
If we ignore the first term of the diff1(n) rows and reverse the order of the remaining terms we get sequence A191488, see the examples; more terms require a higher row number.
Both the diff1(n) and the diff2(n) sequences are related to Gould’s sequence A001316. We ignore the first term and reverse the order of the rest of the terms. The diff2(n) sequence leads directly to A001316, see A191487, while the diff1(n) sequence leads to A001316 in a slightly more complex way. We observe that for Gould’s sequence equation A001316((2*n+1)*2^p-1) = C(p)*A001316(n) with C(p) = 2^p holds, while for its companion A191488 equation A191488((2*n+1)*2^p-1) = C(p)*A001316(n) with C(p) = 2^(p+1)+2 holds; see the Maple program. Furthermore for both sequences a(2^p - 1) = C(p).

Examples

			The first few rows of diff1(n) as a triangle, row lengths A000079(p) with p>=0, are:
[7]
[14, 4]
[36, 8, 6, 4]
[98, 16, 12, 8, 10, 8, 6, 4]
[276, 32, 24, 16, 20, 16, 12, 8, 18, 16, 12, 8, 10, 8, 6, 4]
[794, 64, 48, 32, 40, 32, 24, 16, 36, 32, 24, 16, 20, 16, 12, 8, 34, 32, 24, 16, 20, 16, 12, 8, 18, 16, 12, 8, 10, 8, 6, 4]
The first few rows of diff1(n) reversed minus the first term are:
[4]
[4, 6, 8]
[4, 6, 8, 10, 8, 12, 16]
[4, 6, 8, 10, 8, 12, 16, 18, 8, 12, 16, 20, 16, 24, 32]
[4, 6, 8, 10, 8, 12, 16, 18, 8, 12, 16, 20, 16, 24, 32, 34, 8, 12, 16, 20, 16, 24, 32, 36, 16, 24, 32, 40, 32, 48, 64]
		

Crossrefs

Programs

  • Maple
    nmax:=2^6; pmax:=ceil(log(nmax)/log(2)); A001316 := n -> if n<=-1 then 0 else 2^add(i, i=convert(n, base, 2)) fi: C := proc(p): C(p) := 2^(p+1)+2 end: for p from 0 to pmax do for n from 0 to nmax do a((2*n+1)*2^p-1):= C(p)*A001316(n) od: od: seq(a(n), n=0..nmax-2);

Formula

a((2*n+1)*2^p - 1) = C(p) * A001316(n) with C(p) = (2^(p+1)+2), p>=0.
a(2^p - 1) = 2^(p+1)+2 = A052548(p+1), p>=0.

A100586 Write down the numbers from 3 to infinity. Take next number, M say, that has not been crossed off. Counting through the numbers that have not yet been crossed off after that M, cross off every 5th term. Repeat, always crossing off every 5th term of those that remain. The numbers that are left form the sequence.

Original entry on oeis.org

3, 4, 5, 6, 7, 9, 11, 14, 17, 21, 26, 32, 40, 50, 62, 77, 96, 120, 150, 187, 234, 292, 365, 456, 570, 712, 890, 1112, 1390, 1737, 2171, 2714, 3392, 4240, 5300, 6625, 8281, 10351, 12939, 16174, 20217, 25271, 31589, 39486, 49357, 61696, 77120
Offset: 1

Views

Author

N. J. A. Sloane, Dec 01 2004

Keywords

Crossrefs

Programs

  • Mathematica
    t = Range[3, 80000]; r = {}; While[Length[t] > 0, AppendTo[r, First[t]]; t = Drop[t, {1, -1, 5}];]; r (* Ray Chandler, Dec 02 2004 *)

A133140 a(0) = 2, a(n) = 2^n + 2 for n>=1.

Original entry on oeis.org

2, 4, 6, 10, 18, 34, 66, 130, 258, 514, 1026, 2050, 4098, 8194, 16386, 32770, 65538, 131074, 262146, 524290, 1048578, 2097154, 4194306, 8388610, 16777218, 33554434, 67108866, 134217730, 268435458, 536870914, 1073741826, 2147483650, 4294967298
Offset: 0

Views

Author

Paul Curtz, Sep 21 2007

Keywords

Comments

Sum of the coefficients of the polynomial Q(n,x)=(1+x)[(1+x)^(n-1)+x^(n-1)], Q(0,x)=2.
Also row sums of A133138. - R. J. Mathar, Jun 12 2008

Programs

  • Mathematica
    Table[If[n < 2, 2, 1] + Total[Table[Coefficient[Expand[(1 + x) ((1 + x)^(n - 1) + x^(n - 1))], x^m], {m, 1, n}]], {n, 0, 22}] (* Mats Granvik, May 19 2012 *)
    Join[{2},2^Range[40]+2] (* Harvey P. Dale, Aug 16 2014 *)

Formula

a(n)=2*A094373(n). a(n)=A052548(n), n>0. - R. J. Mathar, Jun 12 2008

Extensions

Edited by R. J. Mathar, Jun 12 2008

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

A283070 Sierpinski tetrahedron or tetrix numbers: a(n) = 2*4^n + 2.

Original entry on oeis.org

4, 10, 34, 130, 514, 2050, 8194, 32770, 131074, 524290, 2097154, 8388610, 33554434, 134217730, 536870914, 2147483650, 8589934594, 34359738370, 137438953474, 549755813890, 2199023255554, 8796093022210, 35184372088834, 140737488355330, 562949953421314
Offset: 0

Views

Author

Peter M. Chema, Feb 28 2017

Keywords

Comments

Number of vertices required to make a Sierpinski tetrahedron or tetrix of side length 2^n. The sum of the vertices (balls) plus line segments (rods) of one tetrix equals the vertices of its larger, adjacent iteration. See formula.
Equivalently, the number of vertices in the (n+1)-Sierpinski tetrahedron graph. - Eric W. Weisstein, Aug 17 2017
Also the independence number of the (n+2)-Sierpinski tetrahedron graph. - Eric W. Weisstein, Aug 29 2021
Final digit alternates 4 and 0.

Crossrefs

Subsequence of A016957.
First bisection of A052548, A087288; second bisection of A049332, A133140, A135440.
Cf. A002023 (edge count).

Programs

Formula

G.f.: 2*(2 - 5*x)/((1 - x)*(1 - 4*x)).
a(n) = 5*a(n-1) - 4*a(n-2) for n > 1.
a(n+1) = a(n) + A002023(n).
a(n) = 2*A052539(n) = A188161(n) - 1 = A087289(n) + 1 = A056469(2*n+2) = A261723(4*n+1).
E.g.f.: 2*(exp(4*x) + exp(x)). - G. C. Greubel, Aug 17 2017

Extensions

Entry revised by Editors of OEIS, Mar 01 2017
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