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 11-15 of 15 results.

A025810 Expansion of 1/((1-x^2)*(1-x^5)*(1-x^10)).

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 3, 3, 3, 3, 3, 3, 6, 3, 6, 3, 6, 6, 6, 6, 6, 6, 10, 6, 10, 6, 10, 10, 10, 10, 10, 10, 15, 10, 15, 10, 15, 15, 15, 15, 15, 15, 21, 15, 21, 15, 21, 21, 21, 21, 21, 21, 28, 21, 28, 21, 28, 28, 28, 28, 28, 28, 36, 28, 36, 28, 36, 36, 36, 36, 36, 36
Offset: 0

Views

Author

Keywords

Comments

Number of partitions of n into parts of size 2, 5, and 10.
a(n) is always a triangular number.

Examples

			G.f. = 1 + x^2 + x^4 + x^5 + x^6 + x^7 + x^8 + x^9 + 3*x^10 + x^11 + 3*x^12 + ...
		

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[1/((1-x^2)(1-x^5)(1-x^10)), {x,0,85}], x]  (* Harvey P. Dale, Apr 06 2011 *)
    a[ n_] := Module[ {m = Mod[n, 10], k}, k = n - m; If[ m == 1 || m == 3, k -= 10]; k (k + 30) / 200 + 1]; (* Michael Somos, Aug 16 2016 *)
  • PARI
    {a(n) = if( n<-16, a(-17 - n), polcoeff( 1 / ((1 - x^2) * (1 - x^5) * (1 - x^10)) + x * O(x^n), n))}; \\ Michael Somos, Mar 18 2012
    
  • PARI
    {a(n) = my(m = n%10); n -= m; if( m==1 || m==3, n -= 10); n * (n + 30) / 200 + 1}; \\ Michael Somos, Aug 16 2016
    
  • PARI
    a(n) = (n^2 + 17*n + (5*n+22)*(-1)^n + 200 + 4*n*[2,-1,1,-2,0][n%5+1])\200 \\ Hoang Xuan Thanh, Aug 28 2025

Formula

G.f.: 1/((1-x^2)(1-x^5)(1-x^10)).
Euler transform of length 10 sequence [ 0, 1, 0, 0, 1, 0, 0, 0, 0, 1]. - Michael Somos, Mar 18 2012
a(n) = a(-17 - n) = a(n - 10) + A008616(n) for all n in Z. - Michael Somos, Mar 18 2012
a(n) = A000217( A008616(n) ) = A000008(n) - A000008(n - 1). - Michael Somos, Dec 15 2002

A182086 Number of ways of making change for n Pfennig using Deutschmark coins.

Original entry on oeis.org

1, 1, 2, 2, 3, 4, 5, 6, 7, 8, 11, 12, 15, 16, 19, 22, 25, 28, 31, 34, 40, 43, 49, 52, 58, 64, 70, 76, 82, 88, 98, 104, 114, 120, 130, 140, 150, 160, 170, 180, 195, 205, 220, 230, 245, 260, 275, 290, 305, 320, 342, 357, 379, 394, 416, 438, 460, 482, 504, 526
Offset: 0

Views

Author

Reinhard Zumkeller, Apr 11 2012

Keywords

Comments

The Pfennig was the subunit of the Deutsche Mark, the currency of Germany until the adoption of the Euro in 2002; the coins were (business strike): 1 Pfg, 2 Pfg, 5 Pfg, 10 Pfg, 50 Pfg, 1 DM = 100 Pfg, 2 DM and 5 DM;
a(n) = A000008(n) for n < 50; a(50) = A000008(50) + 1 = 342;
a(n) = A001312(n) for n < 200; a(200) = A001312(200) + 1 = 26905.
Number of partitions of n into parts 1, 2, 5, 10, 50, 100, 200, and 500. - Joerg Arndt, Jul 08 2013

Examples

			Number of partitions of coin values into coin values:
a(1) = #{1} = 1;
a(2) = #{2, 1+1} = 2;
a(5) = #{5, 2+2+1, 2+1+1+1, 1+1+1+1+1} = 4;
a(10) = #{10, 5+5, 5+2+2+1, 5+2+1+1+1, 5+5x1, 2+2+2+2+2, 2+2+2+2+1+1, 2+2+2+1+1+1+1, 2+2+6x1, 2+8x1, 10x1} = 11;
a(50) = #{50,10+10+10+10+10, 10+10+10+10+5+5, 10+10+10+10+5+2+2+1, 10+10+10+10+5+2+1+1+1, 10+10+10+10+5+10x1, ...} = 342;
a(100) = 2499;
a(200) = 26905;
a(500) = 1229587.
		

Crossrefs

Programs

  • Haskell
    a182086 = p [1,2,5,10,50,100,200,500] where
       p  0 = 1; p []  = 0
       p ks'@(k:ks) m = if m < k then 0 else p ks' (m - k) + p ks m
    
  • Mathematica
    CoefficientList[Series[1/((1 - x)*(1 - x^2)*(1 - x^5)*(1 - x^10)*(1 - x^50)*(1 - x^100)*(1 - x^200)*(1 - x^500)), {x, 0, 50}], x] (* G. C. Greubel, Aug 20 2017 *)
  • PARI
    Vec(1/((1-x)*(1-x^2)*(1-x^5)*(1-x^10)*(1-x^50)*(1-x^100)*(1-x^200)*(1-x^500))+O(x^566)) \\ Joerg Arndt, Jul 08 2013

Formula

G.f.: 1/((1-x)*(1-x^2)*(1-x^5)*(1-x^10)*(1-x^50)*(1-x^100)*(1-x^200)*(1-x^500)). - Joerg Arndt, Jul 08 2013

A367253 The number of ways of making change for 5n cents with Canadian coins (5, 10, 25, 100, 200).

Original entry on oeis.org

1, 1, 2, 2, 3, 4, 5, 6, 7, 8, 10, 11, 13, 14, 16, 18, 20, 22, 24, 26, 30, 32, 36, 38, 42, 46, 50, 54, 58, 62, 68, 72, 78, 82, 88, 94, 100, 106, 112, 118, 128, 134, 144, 150, 160, 170, 180, 190, 200, 210, 224, 234, 248, 258, 272, 286, 300, 314, 328, 342, 362
Offset: 0

Views

Author

Johann Peters, Nov 11 2023

Keywords

Comments

Since 2012 the Canadian penny has been discontinued. The coins now commonly used are the nickel (5 cents), the dime (10 cents), the quarter (25 cents), the loonie (100 cents), and the toonie (200 cents).
Number of partitions of n into parts 1, 2, 5, 20, 40. - Alois P. Heinz, Nov 11 2023

Crossrefs

Programs

  • Mathematica
    a[n_]:=Length[FrobeniusSolve[{5,10,25,100,200},5*n]]; a/@Range[0,100] (* Ivan N. Ianakiev, Nov 21 2023 *)
    CoefficientList[Series[1/((1-x)*(1-x^2)*(1-x^5)*(1-x^20)*(1-x^40)),{x,0,1000}],x] (* Ray Chandler, Nov 22 2023 *)

Formula

From Alois P. Heinz, Nov 11 2023: (Start)
G.f.: 1/((1-x)*(1-x^2)*(1-x^5)*(1-x^20)*(1-x^40)).
a(20*n) = A307849(n). (End)

A267419 Number of ways of making change for n cents using coins whose values are the previous terms in the sequence, starting with 1,2 cents.

Original entry on oeis.org

1, 2, 2, 3, 5, 8, 10, 14, 17, 23, 28, 35, 43, 53, 64, 78, 93, 112, 132, 158, 184, 217, 253, 295, 342, 396, 455, 526, 600, 689, 784, 893, 1014, 1150, 1299, 1468, 1651, 1860, 2084, 2339, 2613, 2921, 3257, 3628, 4034, 4482, 4967, 5508, 6087, 6731, 7426, 8188, 9017, 9920, 10898, 11969, 13120, 14382, 15737, 17215
Offset: 1

Views

Author

Christopher Cormier, Jan 14 2016

Keywords

Examples

			For n=4, the coins available are 1,2. There are a(4)=3 ways to make 4 cents with these coins:
4 = 1+1+1+1
4 = 2+1+1
4 = 2+2
Since there are 3 ways, now the available coins are 1,2,3. For n=5, we have:
5 = 1+1+1+1+1
5 = 2+1+1+1
5 = 2+2+1
5 = 3+1+1
5 = 3+2
for 5 ways to make change, so now 1,2,3,5 are available, etc.
		

Crossrefs

Programs

  • Mathematica
    a = {1, 2}; Do[AppendTo[a, Count[IntegerPartitions@ n, w_ /; AllTrue[w, MemberQ[a, #] &]]], {n, 3, 60}]; a (* Michael De Vlieger, Jan 15 2016, Version 10 *)

A339094 Number of (unordered) ways of making change for n US Dollars using the current US denominations of $1, $2, $5, $10, $20, $50 and $100 bills.

Original entry on oeis.org

1, 1, 2, 2, 3, 4, 5, 6, 7, 8, 11, 12, 15, 16, 19, 22, 25, 28, 31, 34, 41, 44, 51, 54, 61, 68, 75, 82, 89, 96, 109, 116, 129, 136, 149, 162, 175, 188, 201, 214, 236, 249, 271, 284, 306, 328, 350, 372, 394, 416, 451, 473, 508, 530, 565, 600, 635, 670, 705, 740, 793, 828, 881, 916
Offset: 0

Views

Author

Robert G. Wilson v, Nov 25 2020

Keywords

Comments

Not the same as A001313. First difference appears at A001313(100) being 4562, whereas a(100) is 4563; obviously one more than A001313(100).
Not the same as A057537.
Number of partitions of n into parts 1, 2, 5, 10, 20, 50 and 100.

Examples

			a(5) is 4 because 1+1+1+1+1 = 2+1+1+1 = 2+2+1 = 5.
		

Crossrefs

Programs

  • Mathematica
    f[n_] := Length@ IntegerPartitions[n, All, {1, 2, 5, 10, 20, 50, 100}]; Array[f, 75, 0] (* or *)
    CoefficientList[ Series[1/((1 - x) (1 - x^2) (1 - x^5) (1 - x^10) (1 - x^20) (1 - x^50) (1 - x^100)), {x, 0, 75}], x] (* or *)
    Table[ Length@ FrobeniusSolve[{1, 2, 5, 10, 20, 50, 100}, n], {n, 0, 75}] (* much slower *)
  • PARI
    coins(v[..])=my(x='x); prod(i=1, #v, 1/(1-x^v[i]))
    Vec(coins(1, 2, 5, 10, 20, 50, 100)+O(x^99)) \\ Charles R Greathouse IV, Jan 24 2022

Formula

G.f.: 1/((1-x)*(1-x^2)*(1-x^5)*(1-x^10)*(1-x^20)*(1-x^50)*(1-x^100)).
Previous Showing 11-15 of 15 results.