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 21-26 of 26 results.

A054605 a(n) = Sum_{d|6} phi(d)*n^(6/d).

Original entry on oeis.org

0, 6, 84, 780, 4200, 15810, 46956, 118104, 262800, 532350, 1001220, 1773156, 2988024, 4829370, 7532700, 11394480, 16781856, 24143094, 34018740, 47053500, 64008840, 85776306, 113391564, 148049160, 191118000, 244157550, 308934756
Offset: 0

Views

Author

N. J. A. Sloane, Apr 16 2000

Keywords

Crossrefs

Row n=6 of A185651.

Programs

  • Mathematica
    Table[n^6+n^3+2n^2+2n,{n,0,30}] (* or *) LinearRecurrence[{7,-21,35,-35,21,-7,1},{0,6,84,780,4200,15810,46956},30] (* Harvey P. Dale, Mar 11 2023 *)

Formula

a(n) = n^6 + n^3 + 2n^2 + 2n. - Ralf Stephan, Sep 03 2003
G.f.: -6*x*(10*x^4+49*x^3+53*x^2+7*x+1) / (x-1)^7. - Colin Barker, Dec 21 2012

A054606 a(n) = Sum_{d|7} phi(d)*n^(7/d).

Original entry on oeis.org

0, 7, 140, 2205, 16408, 78155, 279972, 823585, 2097200, 4783023, 10000060, 19487237, 35831880, 62748595, 105413588, 170859465, 268435552, 410338775, 612220140, 893871853, 1280000120, 1801088667, 2494358020, 3404825585
Offset: 0

Views

Author

N. J. A. Sloane, Apr 16 2000

Keywords

Crossrefs

Row n=7 of A185651.

Formula

a(n) = n^7 + 6n.
G.f.: 7*x*(x^6+12*x^5+183*x^4+328*x^3+183*x^2+12*x+1) / (x-1)^8. [Colin Barker, Dec 21 2012]

A054607 a(n) = Sum_{d|8} phi(d)*n^(8/d).

Original entry on oeis.org

0, 8, 288, 6672, 65840, 391320, 1681008, 5767328, 16781472, 43053480, 100010240, 214373808, 430002768, 815759672, 1475827920, 2562941760, 4295033408, 6975841608, 11020066272, 16983694160, 25600160880, 37823054808, 54876108848
Offset: 0

Views

Author

N. J. A. Sloane, Apr 16 2000

Keywords

Crossrefs

Row n=8 of A185651.

Programs

Formula

G.f.: -8*x*(34*x^6+525*x^5+1971*x^4+1936*x^3+546*x^2+27*x+1) / (x-1)^9. [Colin Barker, Dec 21 2012]
a(n) = n^8 + n^4 + 2*n^2 + 4*n. - Seiichi Manyama, Jul 11 2021

A054608 a(n) = Sum_{d|9} phi(d)*n^(9/d).

Original entry on oeis.org

0, 9, 540, 19755, 262296, 1953405, 10078164, 40354335, 134218800, 387422001, 1000002060, 2357950419, 5159783880, 10604503845, 20661052356, 38443366215, 68719485024, 118587886425, 198359302140, 322687711611, 512000016120
Offset: 0

Views

Author

N. J. A. Sloane, Apr 16 2000

Keywords

Crossrefs

Row n=9 of A185651.

Programs

Formula

G.f.: 9*x*(x^8 + 50*x^7 + 1640*x^6 + 9774*x^5 + 17390*x^4 + 9774*x^3 + 1640*x^2 + 50*x + 1) / (x - 1)^10. - Colin Barker, Dec 21 2012
a(n) = n^9 + 2*n^3 + 6*n. - Seiichi Manyama, Jul 11 2021

A054609 a(n) = Sum_{d|10} phi(d)*n^(10/d).

Original entry on oeis.org

0, 10, 1080, 59340, 1049680, 9768870, 60474120, 282492280, 1073774880, 3486843810, 10000100440, 25937586180, 61917613680, 137858863870, 289255193640, 576651150960, 1099512677440, 2015995321530, 3570469117560, 6131068735420, 10240003201680, 16679885064150
Offset: 0

Views

Author

N. J. A. Sloane, Apr 16 2000

Keywords

Crossrefs

Row n=10 of A185651.

Programs

  • Mathematica
    Table[DivisorSum[10, EulerPhi[#] n^(10/#) &], {n, 0, 100}] (* T. D. Noe, Mar 27 2012 *)

Formula

G.f.: -10*x*(100*x^8 +4783*x^7 +45547*x^6 +130963*x^5 +131119*x^4 +45469*x^3 +4801*x^2 +97*x +1) / (x -1)^11. [Colin Barker, Dec 21 2012]

A319082 A(n, k) = (1/k)*Sum_{d|k} EulerPhi(d)*n^(k/d) for n >= 0 and k > 0, A(n, 0) = 0, square array read by ascending antidiagonals.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 2, 1, 0, 0, 3, 3, 1, 0, 0, 4, 6, 4, 1, 0, 0, 5, 10, 11, 6, 1, 0, 0, 6, 15, 24, 24, 8, 1, 0, 0, 7, 21, 45, 70, 51, 14, 1, 0, 0, 8, 28, 76, 165, 208, 130, 20, 1, 0, 0, 9, 36, 119, 336, 629, 700, 315, 36, 1, 0, 0, 10, 45, 176, 616, 1560, 2635, 2344, 834, 60, 1, 0, 0, 11, 55, 249, 1044, 3367, 7826, 11165, 8230, 2195, 108, 1, 0
Offset: 0

Views

Author

Peter Luschny, Sep 10 2018

Keywords

Examples

			Array starts:
[n\k][0   1   2    3    4     5      6       7       8        9  ...]
[0]   0,  0,  0,   0,   0,    0,     0,      0,      0,       0, ...
[1]   0,  1,  1,   1,   1,    1,     1,      1,      1,       1, ...
[2]   0,  2,  3,   4,   6,    8,    14,     20,     36,      60, ...
[3]   0,  3,  6,  11,  24,   51,   130,    315,    834,    2195, ...
[4]   0,  4, 10,  24,  70,  208,   700,   2344,   8230,   29144, ...
[5]   0,  5, 15,  45, 165,  629,  2635,  11165,  48915,  217045, ...
[6]   0,  6, 21,  76, 336, 1560,  7826,  39996, 210126, 1119796, ...
[7]   0,  7, 28, 119, 616, 3367, 19684, 117655, 720916, 4483815, ...
		

References

  • D. E. Knuth, Generating All Tuples and Permutations. The Art of Computer Programming, Vol. 4, Fascicle 2, Addison-Wesley, 2005.

Crossrefs

Essentially the same table as A075195.
A185651(n, k) = n*A(k, n).
Main diagonal gives A056665.
A054630(n,k) is a subtriangle for n >= 1 and 1 <= k <= n.

Programs

  • Maple
    with(numtheory):
    A := (n, k) -> `if`(k=0, 0, (1/k)*add(phi(d)*n^(k/d), d=divisors(k))):
    seq(seq(A(n-k, k), k=0..n), n=0..12);
    # Alternatively, row-wise printed as a table:
    T := (n, k) -> `if`(k=0, 0, add(n^igcd(i, k), i=1..k)/k):
    seq(lprint(seq(T(n, k), k=0..9)), n=0..7);
  • PARI
    A(n,k)=if(k==0, 0, sumdiv(k,d, eulerphi(d)*n^(k/d))/k) \\ Andrew Howroyd, Jan 05 2024
  • Sage
    def A319082(n, k):
        return 0 if k == 0 else (1/k)*sum(euler_phi(d)*n^(k//d) for d in divisors(k))
    for n in (0..7):
        print([n], [A319082(n, k) for k in (0..9)])
    

Formula

A(n, k) = (1/k)*Sum_{i=1..k} n^gcd(i, k) for k > 0.
Previous Showing 21-26 of 26 results.