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.

A157406 The integer partitions of n taken as digits in base n+1 and listed in the Hindenburg order.

Original entry on oeis.org

0, 1, 2, 4, 3, 9, 21, 4, 16, 12, 56, 156, 5, 25, 20, 115, 85, 475, 1555, 6, 36, 30, 204, 24, 162, 1086, 114, 792, 5202, 19608, 7, 49, 42, 329, 35, 273, 2121, 217, 210, 1673, 12873, 1169, 9289, 70217, 299593
Offset: 0

Views

Author

Peter Luschny, Mar 11 2009

Keywords

Comments

The rows are enumerated 0,1,2,... Converting the numbers in the n-th row (n>0) to base n+1 gives all partitions of n in the 'Hindenburg order'. The term 'Hindenburg order' is not standard and refers to the partition generating algorithm of C. F. Hindenburg (1779).
The offset of row n (n>0) is A000070[n+1], the length of row n is A000041[n]. The right hand side of the triangle 0,1,4,21,156,... is A060072.

Examples

			[0] <-> [[ ]]
[1] <-> [[1]]
[2,4] <-> [[2],[1,1]]
[3,9,21] <-> [[3],[1,2],[1,1,1]]
[4,16,12,56,156] <-> [[4],[1,3],[2,2],[1,1,2],[1,1,1,1]]
		

Crossrefs

Programs

  • Maple
    a := proc(n) local rev,P,R,i,l,s,k,j;
    rev := l -> [seq(l[nops(l)-j+1],j=1..nops(l))];
    P := rev(combinat[partition](n)); R := NULL;
    for i to nops(P) do l := convert(P[i],base,n+1,10);
    s := add(l[k]*10^(k-1),k=1..nops(l));
    R := R,s; od; R end: [0,seq(a(i),i=1..7)];

A157407 The integer partitions of n taken as digits in base n+1 and listed in the reflected Hindenburg order.

Original entry on oeis.org

0, 1, 4, 2, 21, 6, 3, 156, 32, 12, 8, 4, 1555, 260, 50, 45, 15, 10, 5, 19608, 2802, 408, 114, 402, 66, 24, 60, 18, 12, 6, 299593, 37450, 4690, 658, 4683, 595, 147, 91, 588, 84, 28, 77, 21, 14, 7
Offset: 0

Views

Author

Peter Luschny, Mar 11 2009

Keywords

Comments

The rows are enumerated 0,1,2,... Converting the numbers in the n-th row (n>0) to base n+1 gives all partitions of n in the 'reflected Hindenburg order'. The term 'reflected Hindenburg order' is not standard and refers to the partition generating algorithm of C. F. Hindenburg (1779).
The offset of row n (n>0) is A000070[n+1], the length of row n is A000041[n]. The left hand side of the triangle 0,1,4,21,156,... is A060072.

Examples

			[0] <-> [[ ]]
[1] <-> [[1]]
[4,2] <-> [[1,1],[2]]
[21,6,3] <-> [[1,1,1],[2,1],[3]]
[156,32,12,8,4] <-> [[1,1,1,1],[2,1,1],[2,2],[3,1],[4]]
		

Crossrefs

Programs

  • Maple
    a := proc(n) local rev,P,R,Q,i,l,s,k,j;
    rev := l -> [seq(l[nops(l)-j+1],j=1..nops(l))];
    P := combinat[partition](n); R := NULL;
    for i to nops(P) do Q := rev(P[i]);
    l := convert(Q,base,n+1,10);
    s := add(l[k]*10^(k-1), k=1..nops(l));
    R:= R,s; od; R end: [0,seq(a(i),i=1..7)];

A175151 a(n) = Sum_{i=1..n} ((i+1)^i - 1)/i.

Original entry on oeis.org

1, 5, 26, 182, 1737, 21345, 320938, 5701778, 116812889, 2710555349, 70256770866, 2011763864406, 63066746422417, 2148275748236033, 79009709388692498, 3120334201617871778, 131703367127423550129, 5916556161455825857509, 281857608793034773225930
Offset: 1

Views

Author

Ctibor O. Zizka, Feb 26 2010

Keywords

Crossrefs

Programs

  • Magma
    [(&+[((j+1)^j -1)/j: j in [1..n]]): n in [1..30]]; // G. C. Greubel, Aug 16 2022
    
  • Mathematica
    Accumulate[Table[((i+1)^i-1)/i,{i,20}]] (* Harvey P. Dale, Jul 08 2017 *)
  • SageMath
    [sum(((j+1)^j -1)/j for j in (1..n)) for n in (1..30)] # G. C. Greubel, Aug 16 2022

Formula

a(n) = Sum_{i=1..n+1} A060072(i). - R. J. Mathar, Mar 05 2010
a(n) = Sum_{j=1..n} (j+1)^j/j - H(n), where H(n) is the n-th harmonic number. - G. C. Greubel, Aug 16 2022

Extensions

More terms from R. J. Mathar, Mar 05 2010

A215159 a(n) = floor(n^n / (n+1)).

Original entry on oeis.org

1, 0, 1, 6, 51, 520, 6665, 102942, 1864135, 38742048, 909090909, 23775972550, 685853880635, 21633936185160, 740800455037201, 27368368148803710, 1085102592571150095, 45957792327018709120, 2070863582910344082917, 98920982783015679456198
Offset: 0

Views

Author

Alex Ratushnyak, Aug 04 2012

Keywords

Comments

b(n) = n^n mod (n+1) begins: 0, 1, 1, 3, 1, 5, 1, 7, 1, 9, 1, 11, 1, 13, 1, 15...

Crossrefs

Cf. A060072 is essentially floor((n+1)^n / n).
Cf. A173499 is equal to floor((n-1)^n / n).
Cf. A023037 is essentially floor((n+1)^(n+1) / n).

Programs

  • Magma
    [Floor(n^n/(n+1)): n in [0..30]]; // G. C. Greubel, Aug 16 2022
    
  • Mathematica
    Table[If[n==0, 1, Floor[n^n/(n+1)]], {n,0,30}] (* G. C. Greubel, Aug 16 2022 *)
  • Python
    for n in range(55):
        print(n**n // (n+1), end=",")
    
  • SageMath
    [(n^n//(n+1)) for n in (0..30)] # G. C. Greubel, Aug 16 2022

A177164 a(n) = (n^r - 1)/r^2, where r = (n^(n-1) - 1)/(n-1).

Original entry on oeis.org

1, 5, 9972894583, 449853889404077636694265177903207995382439448590987815041588427345865911961016023550064137351211162870609
Offset: 2

Views

Author

Alexander Adamchuk, May 04 2010

Keywords

Comments

The next term has 1204 digits.
r = (n^(n-1) - 1)/(n-1) = A060072(n) is the (n-1)-digit repunit in base n.
r^2 divides n^r - 1 for all bases n > 1.

Examples

			a(10) = (10^111111111 - 1)/111111111^2.
		

Crossrefs

Programs

  • Mathematica
    Table[(n^((n^(n - 1) - 1)/(n - 1)) - 1)/((n^(n - 1) - 1)/(n - 1))^2, {n, 2, 6}]

Formula

a(n) = (n^((n^(n-1) - 1)/(n-1)) - 1)/((n^(n-1) - 1)/(n-1))^2.
a(n) = (n^A060072(n) - 1)/A060072(n)^2.
Previous Showing 11-15 of 15 results.