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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A351305 a(n) = n^10 * Product_{p|n, p prime} (1 + 1/p^10).

Original entry on oeis.org

1, 1025, 59050, 1049600, 9765626, 60526250, 282475250, 1074790400, 3486843450, 10009766650, 25937424602, 61978880000, 137858491850, 289537131250, 576660215300, 1100585369600, 2015993900450, 3574014536250, 6131066257802, 10250001049600, 16680163512500, 26585860217050
Offset: 1

Views

Author

Wesley Ivan Hurt, Feb 06 2022

Keywords

Comments

Sum of the 10th powers of the divisor complements of the squarefree divisors of n.

Crossrefs

Cf. A008683 (mu).
Sequences of the form n^k * Product_ {p|n, p prime} (1 + 1/p^k) for k=0..10: A034444 (k=0), A001615 (k=1), A065958 (k=2), A065959 (k=3), A065960 (k=4), A351300 (k=5), A351301 (k=6), A351302 (k=7), A351303 (k=8), A351304 (k=9), this sequence (k=10).

Programs

  • Mathematica
    f[p_, e_] := p^(10*e) + p^(10*(e-1)); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 20] (* Amiram Eldar, Feb 08 2022 *)
  • PARI
    a(n)=sumdiv(n, d, moebius(n/d)^2*d^10);
    
  • PARI
    for(n=1, 100, print1(direuler(p=2, n, (1 + X)/(1 - p^10*X))[n], ", ")) \\ Vaclav Kotesovec, Feb 12 2022

Formula

a(n) = Sum_{d|n} d^10 * mu(n/d)^2.
a(n) = n^10 * Sum_{d|n} mu(d)^2 / d^10.
Multiplicative with a(p^e) = p^(10*e) + p^(10*e-10). - Sebastian Karlsson, Feb 08 2022
From Vaclav Kotesovec, Feb 12 2022: (Start)
Dirichlet g.f.: zeta(s)*zeta(s-10)/zeta(2*s).
Sum_{k=1..n} a(k) ~ n^11 * zeta(11) / (11 * zeta(22)) = 1222532449149375 * n^11 * zeta(11) / (155366 * Pi^22).
Sum_{k>=1} 1/a(k) = Product_{primes p} (1 + p^10/(p^20-1)) = 1.000993621149252443797467720671490169127513829380371486971107300011796... (End)

A320974 a(n) = n^n * Product_{p|n, p prime} (1 + 1/p^n).

Original entry on oeis.org

1, 5, 28, 272, 3126, 47450, 823544, 16842752, 387440172, 10009766650, 285311670612, 8918294011904, 302875106592254, 11112685048647250, 437893920912786408, 18447025548686262272, 827240261886336764178, 39346558271492178663450, 1978419655660313589123980
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 25 2018

Keywords

Crossrefs

Programs

  • Mathematica
    Table[n^n Product[1 + Boole[PrimeQ[d]]/d^n, {d, Divisors[n]}], {n, 19}]
    Table[SeriesCoefficient[Sum[MoebiusMu[k]^2 PolyLog[-n, x^k], {k, 1, n}], {x, 0, n}], {n, 19}]
    Table[Sum[MoebiusMu[n/d]^2 d^n, {d, Divisors[n]}], {n, 19}]

Formula

a(n) = [x^n] Sum_{k>=1} mu(k)^2*PolyLog(-n,x^k), where PolyLog() is the polylogarithm function.
a(n) = Sum_{d|n} mu(n/d)^2*d^n.
a(n) = A320973(n,n).

A320973 Square array A(n,k), n >= 1, k >= 0, read by antidiagonals: A(n,k) = n^k * Product_{p|n, p prime} (1 + 1/p^k).

Original entry on oeis.org

1, 1, 2, 1, 3, 2, 1, 5, 4, 2, 1, 9, 10, 6, 2, 1, 17, 28, 20, 6, 4, 1, 33, 82, 72, 26, 12, 2, 1, 65, 244, 272, 126, 50, 8, 2, 1, 129, 730, 1056, 626, 252, 50, 12, 2, 1, 257, 2188, 4160, 3126, 1394, 344, 80, 12, 4, 1, 513, 6562, 16512, 15626, 8052, 2402, 576, 90, 18, 2
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 25 2018

Keywords

Examples

			Square array begins:
  1,   1,   1,    1,     1,     1,  ...
  2,   3,   5,    9,    17,    33,  ...
  2,   4,  10,   28,    82,   244,  ...
  2,   6,  20,   72,   272,  1056,  ...
  2,   6,  26,  126,   626,  3126,  ...
  4,  12,  50,  252,  1394,  8052,  ...
		

Crossrefs

Columns k=0..4 give A034444, A001615, A065958, A065959, A065960.
Cf. A008683, A059379, A059380, A320974 (diagonal).

Programs

  • Mathematica
    Table[Function[k, n^k Product[1 + Boole[PrimeQ[d]]/d^k, {d, Divisors[n]}]][i - n], {i, 0, 11}, {n, 1, i}] // Flatten
    Table[Function[k, SeriesCoefficient[Sum[MoebiusMu[j]^2 PolyLog[-k, x^j], {j, 1, n}], {x, 0, n}]][i - n], {i, 0, 11}, {n, 1, i}] // Flatten
    Table[Function[k, Sum[MoebiusMu[n/d]^2 d^k, {d, Divisors[n]}]][i - n], {i, 0, 11}, {n, 1, i}] // Flatten

Formula

G.f. of column k: Sum_{j>=1} mu(j)^2*PolyLog(-k,x^j), where PolyLog() is the polylogarithm function.
A(n,k) = Sum_{d|n} mu(n/d)^2*d^k.

A194533 Jordan function ratio J_8(n)/J_2(n).

Original entry on oeis.org

1, 85, 820, 5440, 16276, 69700, 120100, 348160, 597780, 1383460, 1786324, 4460800, 4855540, 10208500, 13346320, 22282240, 24221380, 50811300, 47176564, 88541440, 98482000, 151837540, 148316260, 285491200, 254312500, 412720900, 435781620, 653344000, 595531444
Offset: 1

Views

Author

R. J. Mathar, Aug 28 2011

Keywords

Crossrefs

Programs

  • Mathematica
    f[p_, e_] := p^(6*(e - 1))*(p^2 + 1)*(p^4 + 1); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Nov 01 2022 *)

Formula

a(n) = A069093(n)/A007434(n) = A065960(n) * A065958(n).
Multiplicative with a(p^e) = p^(6*(e-1))*(p^2+1)*(p^4+1), e>0.
Dirichlet g.f.: zeta(s-6)*Product_{primes p} (1+p^(4-s)+p^(2-s)+p^(-s)).
Dirichlet convolution of A001014 with the multiplicative sequence 1, 21, 91, 0, 651, 1911, 2451, 0, 0, 13671, 14763, 0, 28731, 51471...
Sum_{k=1..n} a(k) ~ c * n^7 / 7, where c = Product_{primes p} (1 + 1/p^3 + 1/p^5 + 1/p^7) = 1.22847463998021088097249049512949441921891884186337179613337753... - Vaclav Kotesovec, Dec 18 2019
Previous Showing 11-14 of 14 results.