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 12 results. Next

A002577 Number of partitions of 2^n into powers of 2.

Original entry on oeis.org

1, 2, 4, 10, 36, 202, 1828, 27338, 692004, 30251722, 2320518948, 316359580362, 77477180493604, 34394869942983370, 27893897106768940836, 41603705003444309596874, 114788185359199234852802340, 588880400923055731115178072778, 5642645813427132737155703265972004
Offset: 0

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Author

Keywords

Comments

For given m, the general formula for t_m(n, k) and the corresponding tables T, computed as in the example, determine a family of related sequences (placed in the rows or in the columns of T). For example, the numbers from the second row of T, computed for given m and n > 2, are the (m+2)-gonal numbers. So the second row contains the first members of: A000290 (the square numbers) when m=2, A000326 (the pentagonal numbers) when m=3, and so on. But rows IV, V etc. of the given table are not represented in the OEIS till now. - Valentin Bakoev, Feb 25 2009; edited by M. F. Hasler, Feb 09 2014

Examples

			To compute t_2(6,1) we can use a table T, defined as T[i,j]= t_2(i,j), for i=1,2,...,6(=n), and j= 0,1,2,...,32(= k*m^{n-1}). It is: 1,2,3,4,5,6,7,8,9...,33; 1,4,9,16,25,36,49...,81; (so the second row contains the first members of A000290 -- the square numbers) 1,10,35,84,165,...,969; (so the third row contains the first members of A000447. The r-th tetrahedral number is given by formula r(r+1)(r+2)/6. This row (also A000447) contains the tetrahedral numbers, obtained for r=1,3,5,7,...) 1,36,201,656,1625; 1,202,1827; 1,1828; Column 1 contains the first 6 members of A002577. - _Valentin Bakoev_, Feb 25 2009
G.f. = 1 + 2*x + 4*x^2 + 10*x^3 + 36*x^4 + 202*x^5 + 1828*x^6 + ...
		

References

  • R. F. Churchhouse, Binary partitions, pp. 397-400 of A. O. L. Atkin and B. J. Birch, editors, Computers in Number Theory. Academic Press, NY, 1971.
  • Lawrence, Jim. "Dual-Antiprisms and Partitions of Powers of 2 into Powers of 2." Discrete & Computational Geometry, Vol. 16 (2019): 465-478. See page 466.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

a(n) = A000123(2^(n-1)) = A018818(2^n).
Column k=2 of A145515, diagonal of A152977. - Alois P. Heinz, Mar 25 2012
See also A002575, A002576.
A column of A125790.

Programs

  • Haskell
    import Data.MemoCombinators (memo2, list, integral)
    a002577 n = a002577_list !! n
    a002577_list = f [1] where
       f xs = (p' xs $ last xs) : f (1 : map (* 2) xs)
       p' = memo2 (list integral) integral p
       p  0 = 1; p []  = 0
       p ks'@(k:ks) m = if m < k then 0 else p' ks' (m - k) + p' ks m
    -- Reinhard Zumkeller, Nov 27 2015
  • Maple
    A002577 := proc(n) if n<=1 then n+1 else A000123(2^(n-1)); fi; end;
  • Mathematica
    $RecursionLimit = 10^5; (* b = A000123 *) b[0] = 1; b[n_?EvenQ] := b[n] = b[n-1] + b[n/2]; b[n_?OddQ] := b[n] = b[n-1] + b[(n-1)/2]; a[n_] := b[2^(n-1)]; a[0] = 1; Table[a[n], {n, 0, 17}] (* Jean-François Alcover, Nov 23 2011 *)
    a[ n_] := SeriesCoefficient[ 1 / Product[ 1 - x^2^k, {k, 0, n}], {x, 0, 2^n}]; (* Michael Somos, Apr 21 2014 *)
  • PARI
    a(n)=polcoeff(prod(j=0,n,1/(1-x^(2^j)+x*O(x^(2^n)))),2^n) \\ Paul D. Hanna
    

Formula

a(n) is about 0.9233*Sum_j {i=0, 1, 2, 3, ...} 2^(j*(2n-j-1)/2)/j!. - Henry Bottomley, Jul 23 2003
a(n) = A078121(n+1, 1). - Paul D. Hanna, Sep 13 2004
A002577(n)-1 = A125792(n). - Let m > 1, n > 0 and k >= 0. The general formula for the number of all partitions of k*m^n into powers of m is t_m(n, k)= k+1 if n=1, t_m(n, k)= 1 if k=0, and t_m(n, k)= t_m(n, k-1) + t_m(n-1, k*m) if n > 1 and k > 0. A002577 is obtained for m=2 and n=1,2,3,... - Valentin Bakoev, Feb 25 2009
a(n) = [x^(2^n)] 1/Product_{j>=0} (1-x^(2^j)). - Alois P. Heinz, Sep 27 2011

Extensions

Edited by M. F. Hasler, Feb 09 2014

A094373 Expansion of (1-x-x^2)/((1-x)*(1-2*x)).

Original entry on oeis.org

1, 2, 3, 5, 9, 17, 33, 65, 129, 257, 513, 1025, 2049, 4097, 8193, 16385, 32769, 65537, 131073, 262145, 524289, 1048577, 2097153, 4194305, 8388609, 16777217, 33554433, 67108865, 134217729, 268435457, 536870913, 1073741825, 2147483649, 4294967297, 8589934593
Offset: 0

Views

Author

Paul Barry, Apr 28 2004

Keywords

Comments

Partial sum of 1,1,1,2,4,8,...
Binomial transform of abs(A073097).
Binomial transform is A094374.
Partial sums are in A006127. - Paul Barry, Aug 05 2004
An elephant sequence, see A175654. For the corner squares four A[5] vectors, with decimal values 2, 8, 32 and 128, lead to this sequence. For the central square these vectors lead to the companion sequence A011782. - Johannes W. Meijer, Aug 15 2010
This sequence has a(0) = 1 and for all n > 0, a(n) = 2^(n-1)+1. Consequently 2*a(n) >= a(n+1) for all n > 0 and the sequence is complete. - Frank M Jackson, Jan 29 2012
Row lengths of the triangle in A198069. - Reinhard Zumkeller, May 26 2013
Take A007843 and count the repeated values. The result is 1,1,2,1,3,1,2,1,4,1,2,1,3,1,2,1,5,.... Build a third sequence, where a(1) = 1 and a(n) equals the length (greater than 1) of the shortest palindromic subsequence of consecutive terms of the second sequence starting with a(n) of the second sequence. The third sequence starts 1,3,5,3,9,3,5,3,17,3,5,3,9,3,5,3,33,.... Conjecturally, in the third sequence: (1) the indices of the first occurrence of each value form the present sequence and (2) for n>1, a(n) is in the a(n-1)-th position. - Ivan N. Ianakiev, Aug 20 2019

Examples

			G.f. = 1 + 2*x + 3*x^2 + 5*x^3 + 9*x^4 + 17*x^5 + 33*x^6 + 65*x^7 + ...
		

Crossrefs

Apart from the initial 1, identical to A000051.
Cf. A135225.
Column k=1 of A152977.
Row n=2 of A238016.

Programs

  • GAP
    a:=[2,3];; for n in [3..40] do a[n]:=3*a[n-1]-2*a[n-2]; od; Concatenation([1], a); # G. C. Greubel, Nov 06 2019
  • Magma
    [(2^n-0^n)/2+1: n in [0..40]]; // Vincenzo Librandi, Jun 10 2011
    
  • Magma
    R:=PowerSeriesRing(Integers(), 35); Coefficients(R!( (1-x-x^2)/((1-x)*(1-2*x)))); // Marius A. Burtea, Oct 25 2019
    
  • Maple
    1, seq((2^n - 0^n)/2 +1, n=1..40); # G. C. Greubel, Nov 06 2019
  • Mathematica
    CoefficientList[Series[(1-x-x^2)/((1-x)*(1-2*x)), {x, 0, 40}], x] (* or *) Join[{1}, LinearRecurrence[{3, -2}, {2, 3}, 40]] (* Vladimir Joseph Stephan Orlovsky, Jan 22 2012 *)
    a[ n_]:= If[n<0, 0, 1 + Quotient[2^n, 2]]; (* Michael Somos, May 26 2014 *)
    a[ n_]:= SeriesCoefficient[(1-x-x^2)/((1-x)(1-2x)), {x, 0, n}]; (* Michael Somos, May 26 2014 *)
    LinearRecurrence[{3,-2},{1,2,3},40] (* Harvey P. Dale, Aug 09 2015 *)
  • PARI
    a(n)=2^n\2+1 \\ Charles R Greathouse IV, Apr 05 2013
    
  • PARI
    Vec((1-x-x^2)/((1-x)*(1-2*x))+O(x^40)) \\ Charles R Greathouse IV, Apr 05 2013
    
  • Sage
    [(2^n - 0^n)/2 + 1 for n in (0..40)] # G. C. Greubel, Nov 06 2019
    

Formula

a(n) = (2^n - 0^n)/2 + 1.
a(n) = 3*a(n-1) - 2*a(n-2).
a(2*n) = 2*a(2*n-1) - 1, n>0.
Row sums of triangle A135225. - Gary W. Adamson, Nov 23 2007
a(n) = A131577(n) + 1. - Paul Curtz, Aug 07 2008
a(n) = 2*a(n-1) - 1 for n>1, a(0)=1, a(1)=2. - Philippe Deléham, Sep 25 2009
E.g.f.: exp(x)*(1 + sinh(x)). - Arkadiusz Wesolowski, Aug 13 2012
G.f.: G(0), where G(k)= 1 + 2^k*x/(1 - x/(x + 2^k*x/G(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Jul 26 2013
a(n) = 2^(n-1) +1 = A000051(n-1) for n>0. - M. F. Hasler, Sep 22 2013

A125792 Column 2 of table A125790; also equals row sums of matrix power A078121^2.

Original entry on oeis.org

1, 3, 9, 35, 201, 1827, 27337, 692003, 30251721, 2320518947, 316359580361, 77477180493603, 34394869942983369, 27893897106768940835, 41603705003444309596873, 114788185359199234852802339, 588880400923055731115178072777, 5642645813427132737155703265972003
Offset: 0

Views

Author

Paul D. Hanna, Dec 10 2006

Keywords

Comments

Triangle A078121 shifts left one column under matrix square and is related to partitions into powers of 2.
Number of partitions of 2^n into powers of 2, excluding the trivial partition 2^n=2^n. - Valentin Bakoev, Feb 15 2009

Examples

			G.f.: 1 + 3*x + 9*x^2 + 35*x^3 + 201*x^4 + 1827*x^5 + 27337*x^6 + 692003*x^7 + ...
To obtain t_2(5,1) we use the table T, defined as T[i,j]= t_2(i,j), for i=1,2,...,5(=n), and j= 0,1,2,...,16(= k*m^{n-1}). It is 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1 1,3,5,7,9,11,13,15,17 1,9,25,49,81 1,35,165 1,201 Column 1 contains the first 5 members of A125792. [_Valentin Bakoev_, Feb 15 2009]
		

Crossrefs

Adding 1 to the members of A125792 we obtain A002577. [Valentin Bakoev, Feb 15 2009]
A diagonal of A152977.

Programs

  • Maple
    g:= proc(b, n, k) option remember; local t; if b<0 then 0 elif b=0 or n=0 or k<=1 then 1 elif b>=n then add(g(b-t, n, k) *binomial(n+1, t) *(-1)^(t+1), t=1..n+1); else g(b-1, n, k) +g(b*k, n-1, k) fi end: a:= n-> g(1, n+1,2)-1: seq(a(n), n=0..25);  # Alois P. Heinz, Feb 27 2009
  • Mathematica
    T[n_, k_] := T[n, k] = T[n, k-1] + T[n-1, 2*k]; T[0, ] = T[, 0] = 1; Table[T[n, 2], {n, 0, 20} ] (* Jean-François Alcover, Jun 15 2015 *)
  • PARI
    {a(n)=local(p=2,q=2,A=Mat(1), B); for(m=1, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i||j==1, B[i, j]=1, B[i, j]=(A^q)[i-1, j-1]); )); A=B); return(sum(c=0,n,(A^p)[n+1,c+1]))}
    for(n=0,25,print1(a(n),", "))
    
  • PARI
    {a(n, k=3) = if(n<1, n==0, sum(i=1, k, a(n-1, 2*i-1)))}; /* Michael Somos, Nov 24 2016 */

Formula

Is this sequence the same as A002575 (coefficients of Bell's formula)?
Denote the sum m^n + m^n + ... + m^n, k times, by k*m^n (m > 1, n > 0 and k are natural numbers). The general formula for the number of all partitions of the sum k*m^n into powers of m, smaller than m^n, is t_m(n, k)= 1 when n=1 or k=0, or = t_m(n, k-1) + Sum_{j=1..m} t_m(n-1, (k-1)*n+j), when n > 1 and k > 0. A125792 is obtained for m=2 and n=1,2,3,... [Valentin Bakoev, Feb 15 2009]
a(n) = A145515(n+1,2)-1. - Alois P. Heinz, Feb 27 2009
From Benedict W. J. Irwin, Nov 16 2016: (Start)
Conjecture: a(n+1) = Sum_{i_1=1..3} Sum_{i_2=1..2*i_1-1} ... Sum_{i_n=1..2*i_(n-1)-1} (2*i_n - 1). For example:
a(2) = Sum_{i=1..3} 2*i-1.
a(3) = Sum_{i=1..3} Sum_{j=1..2*i-1} 2*j-1.
a(4) = Sum_{i=1..3} Sum_{j=1..2*i-1} Sum_{k=1..2*j-1} 2*k-1. (End)

A125794 Column 4 of table A125790; also equals row sums of matrix power A078121^4.

Original entry on oeis.org

1, 5, 25, 165, 1625, 25509, 664665, 29559717, 2290267225, 314039061413, 77160820913241, 34317392762489765, 27859502236825957465, 41575811106337540656037, 114746581654195790543205465, 588765612737696531880325270437, 5642056933026209681424588087899225
Offset: 0

Views

Author

Paul D. Hanna, Dec 10 2006

Keywords

Comments

Triangle A078121 shifts left one column under matrix square and is related to partitions into powers of 2.

Crossrefs

A diagonal of A152977.

Programs

  • PARI
    a(n)=local(p=4,q=2,A=Mat(1), B); for(m=1, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i || j==1, B[i, j]=1, B[i, j]=(A^q)[i-1, j-1]); )); A=B); return(sum(c=0,n,(A^p)[n+1,c+1]))

A210772 Number of partitions of 2^n into powers of 2 less than or equal to 8.

Original entry on oeis.org

1, 2, 4, 10, 35, 165, 969, 6545, 47905, 366145, 2862209, 22632705, 180007425, 1435853825, 11470030849, 91693092865, 733276217345, 5865135816705, 46916791205889, 375317149057025, 3002468471537665, 24019472891510785, 192154683614691329, 1537233070859485185
Offset: 0

Views

Author

Alois P. Heinz, Mar 26 2012

Keywords

Examples

			a(3) = 10 because there are 10 partitions of 2^3 = 8 into powers of 2 less than or equal to 8: [1,1,1,1,1,1,1,1], [2,1,1,1,1,1,1], [2,2,1,1,1,1], [2,2,2,1,1], [2,2,2,2], [4,1,1,1,1], [4,2,1,1], [4,2,2], [4,4], [8].
		

Crossrefs

Column k=3 of A152977.

Programs

  • Maple
    a:= n-> `if`(n<2, 2^n, (Matrix(4, (i, j)-> `if`(i=j-1, 1, `if`(i=4,
         [-64, 120, -70, 15][j], 0)))^(n-2). <<4, 10, 35, 165>>)[1,1]):
    seq(a(n), n=0..30);
  • Mathematica
    LinearRecurrence[{15,-70,120,-64},{1,2,4,10,35,165},30] (* Harvey P. Dale, Aug 27 2022 *)
  • PARI
    Vec((1 - 13*x + 44*x^2 - 30*x^3 - 11*x^4 - 12*x^5) / ((1 - x)*(1 - 2*x)*(1 - 4*x)*(1 - 8*x)) + O(x^40)) \\ Colin Barker, Jan 26 2018

Formula

G.f.: -(12*x^5+11*x^4+30*x^3-44*x^2+13*x-1)/Product_{j=0..3} (2^j*x-1).
a(n) = [x^2^(n-1)] 1/(1-x) * 1/Product_{j=0..2} (1-x^(2^j)) for n>0.
a(n) = 1 + (11*2^(n-3))/3 + 2^(3*n-7)/3 + 4^(n-2) for n>1. - Colin Barker, Jan 26 2018

A210773 Number of partitions of 2^n into powers of 2 less than or equal to 16.

Original entry on oeis.org

1, 2, 4, 10, 36, 201, 1625, 17361, 222241, 3160641, 47594625, 738433281, 11633144321, 184687354881, 2943499290625, 47004182220801, 751333186150401, 12015464030289921, 192200500444954625, 3074832660977745921, 49194319991205396481, 787085099922532597761
Offset: 0

Views

Author

Alois P. Heinz, Mar 26 2012

Keywords

Crossrefs

Column k=4 of A152977.

Programs

  • Maple
    a:= n-> `if`(n<4, [1, 2, 4, 10][n+1], (Matrix(5, (i, j)-> `if`(i=j-1, 1, `if`(i=5, [1024, -1984, 1240, -310, 31][j], 0)))^(n-4). <<36, 201, 1625, 17361, 222241>>)[1,1]): seq(a(n), n=0..30);
  • Mathematica
    LinearRecurrence[{31,-310,1240,-1984,1024},{1,2,4,10,36,201,1625,17361,222241},30] (* Harvey P. Dale, Oct 02 2020 *)

Formula

G.f.: (256*x^8-400*x^7-42*x^6-169*x^5-470*x^4+734*x^3-252*x^2+29*x-1) / Product_{j=0..4} (2^j*x-1).
a(n) = [x^2^(n-1)] 1/(1-x) * 1/Product_{j=0..3} (1-x^(2^j)) for n>0.

A210774 Number of partitions of 2^n into powers of 2 less than or equal to 32.

Original entry on oeis.org

1, 2, 4, 10, 36, 202, 1827, 25509, 497097, 12070289, 333620001, 9898583617, 304816671873, 9567029991681, 303182221750785, 9654673365689345, 308196987575257089, 9850278328626941953, 315016627560700387329, 10077456621734453460993, 322429412555504845881345
Offset: 0

Views

Author

Alois P. Heinz, Mar 26 2012

Keywords

Crossrefs

Column k=5 of A152977.

Programs

  • Maple
    a:= n-> `if`(n<5, [1, 2, 4, 10, 36][n+1], (Matrix(6, (i, j)-> `if`(i=j-1, 1, `if`(i=6, [-32768, 64512, -41664, 11160, -1302, 63][j], 0)))^(n-5). <<202, 1827, 25509, 497097, 12070289, 333620001>>)[1,1]): seq(a(n), n=0..20);

Formula

G.f.: -(2048*x^9 -320*x^8 +4220*x^7 +5227*x^6 +14870*x^5 -23958*x^4 +8798*x^3 -1180*x^2 +61*x -1) / Product_{j=0..5} (2^j*x-1).
a(n) = [x^2^(n-1)] 1/(1-x) * 1/Product_{j=0..4} (1-x^(2^j)) for n>0.

A210775 Number of partitions of 2^n into powers of 2 less than or equal to 64.

Original entry on oeis.org

1, 2, 4, 10, 36, 202, 1828, 27337, 664665, 23693265, 1092226081, 58686573121, 3431048928385, 209706732148993, 13113096655221249, 829504773400454145, 52778852611947546625, 3367976225848670392321, 215235141069830389702657, 13764966441742878856593409
Offset: 0

Views

Author

Alois P. Heinz, Mar 26 2012

Keywords

Crossrefs

Column k=6 of A152977.

Programs

  • Maple
    a:= n-> `if`(n<7, [1, 2, 4, 10, 36, 202, 1828][n+1], (Matrix(7, (i, j)-> `if`(i=j-1, 1, `if`(i=7, [2097152, -4161536, 2731008, -755904, 94488, -5334, 127][j], 0)))^(n-6). <<1828, 27337, 664665, 23693265, 1092226081, 58686573121, 3431048928385>>)[1,1]): seq(a(n), n=0..20);

Formula

G.f.: -(7864320*x^12 -12132352*x^11 +4458752*x^10 -24624*x^9 +211146*x^8 +332009*x^7 +946454*x^6 -1548182*x^5 +587030*x^4 -84318*x^3 +5084*x^2 -125*x+1) / Product_{j=0..6} (2^j*x-1).
a(n) = [x^2^(n-1)] 1/(1-x) * 1/Product_{j=0..5} (1-x^(2^j)) for n>0.

A210776 Number of partitions of 2^n into powers of 2 less than or equal to 128.

Original entry on oeis.org

1, 2, 4, 10, 36, 202, 1828, 27338, 692003, 29559717, 1933411785, 169368653201, 17695666168609, 2038699559609921, 247324139826203777, 30811717563505088769, 3890604470232727499265, 494612931489164269609985, 63094694253683687355107329
Offset: 0

Views

Author

Alois P. Heinz, Mar 26 2012

Keywords

Crossrefs

Column k=7 of A152977.

Programs

  • Maple
    gf:= (1 +(-253 +(21084 +(-735070 +(11379734 +(-76688022 +(199113750 +(-120814102 +(-42258923 +(-28134460 +(-57698752+(1018234880 +(-4990304256 +4009754624*x) *x) *x) *x) *x) *x) *x) *x) *x) *x) *x) *x) *x)/ mul(2^j*x-1, j=0..7): a:= n-> coeff(series(gf, x, n+1), x, n): seq(a(n), n=0..20);

Formula

G.f.: (4009754624*x^13 -4990304256*x^12 +1018234880*x^11 -57698752*x^10 -28134460*x^9 -42258923*x^8 -120814102*x^7 +199113750*x^6 -76688022*x^5 +11379734*x^4-735070*x^3+21084*x^2-253*x+1)/Product_{j=0..7} (2^j*x-1).
a(n) = [x^2^(n-1)] 1/(1-x) * 1/Product_{j=0..6} (1-x^(2^j)) for n>0.

A210777 Number of partitions of 2^n into powers of 2 less than or equal to 256.

Original entry on oeis.org

1, 2, 4, 10, 36, 202, 1828, 27338, 692004, 30251721, 2290267225, 275723872209, 45943934602273, 9336623954364993, 2119856439870545025, 510453118614955153665, 126696287737269468934657, 31933986928271408429425665, 8111646059635412792802330625
Offset: 0

Views

Author

Alois P. Heinz, Mar 26 2012

Keywords

Crossrefs

Column k=8 of A152977.

Programs

  • Maple
    gf:= (-1 +(509 +(-85852 +(6132574 +(-199557654 +(2989899926 +(-19831247382 +(51093934102 +(-30886151190 +(-10790841321 +(-7148051274 +(100712240 +(-272750006528 +(-281547988992 +(28916158300160 +(-83085001490432 +54717883351040*x) *x) *x) *x) *x) *x) *x) *x) *x) *x) *x) *x) *x) *x) *x) *x)/ mul(2^j*x-1, j=0..8): a:= n-> coeff(series(gf, x, n+1), x, n): seq(a(n), n=0..20);

Formula

G.f.: (54717883351040*x^16 -83085001490432*x^15 +28916158300160*x^14 -281547988992*x^13 -272750006528*x^12 +100712240*x^11 -7148051274*x^10 -10790841321*x^9 -30886151190*x^8 +51093934102*x^7 -19831247382*x^6 +2989899926*x^5 -199557654*x^4 +6132574*x^3 -85852*x^2 +509*x-1) / Product_{j=0..8} (2^j*x-1).
a(n) = [x^2^(n-1)] 1/(1-x) * 1/Product_{j=0..7} (1-x^(2^j)) for n>0.
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