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

A059376 Jordan function J_3(n).

Original entry on oeis.org

1, 7, 26, 56, 124, 182, 342, 448, 702, 868, 1330, 1456, 2196, 2394, 3224, 3584, 4912, 4914, 6858, 6944, 8892, 9310, 12166, 11648, 15500, 15372, 18954, 19152, 24388, 22568, 29790, 28672, 34580, 34384, 42408, 39312, 50652, 48006, 57096
Offset: 1

Views

Author

N. J. A. Sloane, Jan 28 2001

Keywords

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 199, #3.
  • R. Sivaramakrishnan, "The many facets of Euler's totient. II. Generalizations and analogues", Nieuw Arch. Wisk. (4) 8 (1990), no. 2, 169-187.

Crossrefs

See A059379 and A059380 (triangle of values of J_k(n)), A000010 (J_1), A007434 (J_2), A059377 (J_4), A059378 (J_5), A069091 - A069095 (J_6 through J_10).

Programs

  • Maple
    J := proc(n,k) local i,p,t1,t2; t1 := n^k; for p from 1 to n do if isprime(p) and n mod p = 0 then t1 := t1*(1-p^(-k)); fi; od; t1; end; # (with k = 3)
    A059376 := proc(n)
        add(d^3*numtheory[mobius](n/d),d=numtheory[divisors](n)) ;
    end proc: # R. J. Mathar, Nov 03 2015
  • Mathematica
    JordanJ[n_, k_: 1] := DivisorSum[n, #^k*MoebiusMu[n/#] &]; f[n_] := JordanJ[n, 3]; Array[f, 39]
    f[p_, e_] := p^(3*e) - p^(3*(e-1)); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Oct 12 2020 *)
  • PARI
    for(n=1,120,print1(sumdiv(n,d,d^3*moebius(n/d)),","))
    
  • PARI
    for (n = 1, 1000, write("b059376.txt", n, " ", sumdiv(n, d, d^3*moebius(n/d))); ) \\ Harry J. Smith, Jun 26 2009
    
  • PARI
    seq(n) = dirmul(vector(n,k,k^3), vector(n,k,moebius(k)));
    seq(39)  \\ Gheorghe Coserea, May 11 2016
    
  • Python
    from math import prod
    from sympy import factorint
    def A059376(n): return prod(p**(3*(e-1))*(p**3-1) for p, e in factorint(n).items()) # Chai Wah Wu, Jan 29 2024

Formula

Multiplicative with a(p^e) = p^(3e) - p^(3e-3). - Vladeta Jovovic, Jul 26 2001
a(n) = Sum_{d|n} d^3*mu(n/d). - Benoit Cloitre, Apr 05 2002
Dirichlet generating function: zeta(s-3)/zeta(s). - Franklin T. Adams-Watters, Sep 11 2005
A063453(n) divides a(n). - R. J. Mathar, Mar 30 2011
a(n) = Sum_{k=1..n} gcd(k,n)^3 * cos(2*Pi*k/n). - Enrique Pérez Herrero, Jan 18 2013
a(n) = n^3*Product_{distinct primes p dividing n} (1-1/p^3). - Tom Edgar, Jan 09 2015
G.f.: Sum_{n>=1} a(n)*x^n/(1 - x^n) = x*(1 + 4*x + x^2)/(1 - x)^4. - Ilya Gutkovskiy, Apr 25 2017
Sum_{d|n} a(d) = n^3. - Werner Schulte, Jan 12 2018
Sum_{k=1..n} a(k) ~ 45*n^4 / (2*Pi^4). - Vaclav Kotesovec, Feb 07 2019
From Amiram Eldar, Oct 12 2020: (Start)
lim_{n->oo} (1/n) * Sum_{k=1..n} a(k)/k^3 = 1/zeta(4) (A215267).
Sum_{n>=1} 1/a(n) = Product_{p prime} (1 + p^3/(p^3-1)^2) = 1.2253556451... (End)
O.g.f.: Sum_{n >= 1} mu(n)*x^n*(1 + 4*x^n + x^(2*n))/(1 - x^n)^4 = x + 7*x^2 + 26*x^3 + 56*x^4 + 124*x^5 + .... - Peter Bala, Jan 31 2022
From Peter Bala, Jan 01 2024: (Start)
a(n) = Sum_{d divides n} d * J_2(d) * phi(n/d) = Sum_{d divides n} d^2 * phi(d) * J_2(n/d), where J_2(n) = A007434(n).
a(n) = Sum_{k = 1..n} gcd(k, n) * J_2(gcd(k, n)) = Sum_{1 <= j, k <= n} gcd(j, k, n)^2 * J_1(gcd(j, k, n)). (End)
a(n) = Sum_{1 <= i, j <= n, lcm(i, j) = n} phi(i)*J_2(j) = Sum_{1 <= i, j, k <= n, lcm(i, j, k) = n} phi(i)*phi(j)*phi(k), where J_2(n) = A007434(n). - Peter Bala, Jan 29 2024

A059377 Jordan function J_4(n).

Original entry on oeis.org

1, 15, 80, 240, 624, 1200, 2400, 3840, 6480, 9360, 14640, 19200, 28560, 36000, 49920, 61440, 83520, 97200, 130320, 149760, 192000, 219600, 279840, 307200, 390000, 428400, 524880, 576000, 707280, 748800, 923520, 983040, 1171200, 1252800, 1497600, 1555200, 1874160
Offset: 1

Views

Author

N. J. A. Sloane, Jan 28 2001

Keywords

Comments

This sequence is multiplicative. - Mitch Harris, Apr 19 2005
For n = 4 or n >= 6, a(n) is divisible by 240. - Jianing Song, Apr 06 2019

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 199, #3.
  • R. Sivaramakrishnan, "The many facets of Euler's totient. II. Generalizations and analogues", Nieuw Arch. Wisk. (4) 8 (1990), no. 2, 169-187.

Crossrefs

See A059379 and A059380 (triangle of values of J_k(n)), A000010 (J_1), A007434 (J_2), A059376 (J_3), A059378 (J_5), A069091 - A069095 (J_6 through J_10).
Cf. A013663.

Programs

  • Maple
    J := proc(n,k) local i,p,t1,t2; t1 := n^k; for p from 1 to n do if isprime(p) and n mod p = 0 then t1 := t1*(1-p^(-k)); fi; od; t1; end:
    seq(J(n,4), n=1..40);
  • Mathematica
    JordanJ[n_, k_: 1] := DivisorSum[n, #^k*MoebiusMu[n/#] &]; f[n_] := JordanJ[n, 4]; Array[f, 38]
    f[p_, e_] := p^(4*e) - p^(4*(e-1)); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Oct 12 2020 *)
  • PARI
    for(n=1,100,print1(sumdiv(n,d,d^4*moebius(n/d)),","))
    
  • PARI
    a(n)=if(n<1,0,sumdiv(n,d,d^4*moebius(n/d)))
    
  • PARI
    a(n)=if(n<1,0,dirdiv(vector(n,k,k^4),vector(n,k,1))[n])
    
  • PARI
    { for (n = 1, 1000, write("b059377.txt", n, " ", sumdiv(n, d, d^4*moebius(n/d))); ) } \\ Harry J. Smith, Jun 26 2009

Formula

a(n) = Sum_{d|n} d^4*mu(n/d). - Benoit Cloitre, Apr 05 2002
Multiplicative with a(p^e) = p^(4e)-p^(4(e-1)).
Dirichlet generating function: zeta(s-4)/zeta(s). - Franklin T. Adams-Watters, Sep 11 2005
a(n) = Sum_{k=1..n} gcd(k,n)^4 * cos(2*Pi*k/n). - Enrique Pérez Herrero, Jan 18 2013
a(n) = n^4*Product_{distinct primes p dividing n} (1 - 1/p^4). - Tom Edgar, Jan 09 2015
G.f.: Sum_{n>=1} a(n)*x^n/(1 - x^n) = x*(1 + 11*x + 11*x^2 + x^3)/(1 - x)^5. - Ilya Gutkovskiy, Apr 25 2017
Sum_{k=1..n} a(k) ~ n^5 / (5*zeta(5)). - Vaclav Kotesovec, Feb 07 2019
From Amiram Eldar, Oct 12 2020: (Start)
lim_{n->oo} (1/n) * Sum_{k=1..n} a(k)/k^4 = 1/zeta(5).
Sum_{n>=1} 1/a(n) = Product_{p prime} (1 + p^4/(p^4-1)^2) = 1.0870036174... (End)
O.g.f.: Sum_{n >= 1} mu(n)*x^n*(1 + 11*x^n + 11*x^(2*n) + x^(3*n))/(1 - x^n)^5 = x + 15*x^2 + 80*x^3 + 240*x^4 + 624*x^5 + .... - Peter Bala, Jan 31 2022
From Peter Bala, Jan 01 2024: (Start)
a(n) = Sum_{d divides n} d * J_3(d) * J_1(n/d) = Sum_{d divides n} d^2 * J_2(d) * J_2(n/d) = Sum_{d divides n} d^3 * J_1(d) * J_3(n/d), where J_1(n) = phi(n) = A000010(n), J_2(n) = A007434(n) and J(3,n) = A059376(n).
a(n) = Sum_{k = 1..n} gcd(k, n) * J_3(gcd(k, n)) = Sum_{1 <= j, k <= n} gcd(j, k, n)^2 * J_2(gcd(j, k, n)) = Sum_{1 <= i, j, k <= n} gcd(i, j, k, n)^3 * J_1(gcd(i, j, k, n)). (End)
a(n) = Sum_{1 <= i, j <= n, lcm(i, j) = n} J_2(i) * J_2(j) = Sum_{1 <= i, j <= n, lcm(i, j) = n} phi(i) * J_3(j) (apply Lehmer, Theorem 1). - Peter Bala, Jan 29 2024

A059378 Jordan function J_5(n).

Original entry on oeis.org

1, 31, 242, 992, 3124, 7502, 16806, 31744, 58806, 96844, 161050, 240064, 371292, 520986, 756008, 1015808, 1419856, 1822986, 2476098, 3099008, 4067052, 4992550, 6436342, 7682048, 9762500, 11510052, 14289858, 16671552, 20511148, 23436248, 28629150, 32505856
Offset: 1

Views

Author

N. J. A. Sloane, Jan 28 2001

Keywords

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 199, #3.
  • R. Sivaramakrishnan, "The many facets of Euler's totient. II. Generalizations and analogues", Nieuw Arch. Wisk. (4) 8 (1990), no. 2, 169-187.

Crossrefs

See A059379 and A059380 (triangle of values of J_k(n)), A000010 (J_1), A059376 (J_3), A059377 (J_4), A069091 - A069095 (J_6 through J_10).
Cf. A013664.

Programs

  • Maple
    J := proc(n,k) local i,p,t1,t2; t1 := n^k; for p from 1 to n do if isprime(p) and n mod p = 0 then t1 := t1*(1-p^(-k)); fi; od; t1; end; # (with k = 5)
  • Mathematica
    JordanJ[n_, k_] := DivisorSum[n, #^k*MoebiusMu[n/#] &]; f[n_] := JordanJ[n, 5]; Array[f, 30]
    f[p_, e_] := p^(5*e) - p^(5*(e-1)); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Oct 12 2020 *)
  • PARI
    for(n=1,100,print1(sumdiv(n,d,d^5*moebius(n/d)),","))
    
  • PARI
    { for (n = 1, 1000, write("b059378.txt", n, " ", sumdiv(n, d, d^5*moebius(n/d))); ) } \\ Harry J. Smith, Jun 26 2009
    
  • Python
    from sympy import divisors, mobius
    def a(n):
        return sum(d**5 * mobius(n // d) for d in divisors(n))
    # Indranil Ghosh, Apr 26 2017

Formula

a(n) = Sum_{d|n} d^5*mu(n/d). - Benoit Cloitre, Apr 05 2002
Multiplicative with a(p^e) = p^(5e)-p^(5(e-1)).
Dirichlet generating function: zeta(s-5)/zeta(s). - Franklin T. Adams-Watters, Sep 11 2005
a(n) = n^5*Product_{distinct primes p dividing n} (1-1/p^5). - Tom Edgar, Jan 09 2015
G.f.: Sum_{n>=1} a(n)*x^n/(1 - x^n) = x*(1 + 26*x + 66*x^2 + 26*x^3 + x^4)/(1 - x)^6. - Ilya Gutkovskiy, Apr 25 2017
Sum_{k=1..n} a(k) ~ 315*n^6 / (2*Pi^6). - Vaclav Kotesovec, Feb 07 2019
From Amiram Eldar, Oct 12 2020: (Start)
Limit_{n->oo} (1/n) * Sum_{k=1..n} a(k)/k^5 = 1/zeta(6).
Sum_{n>=1} 1/a(n) = Product_{p prime} (1 + p^5/(p^5-1)^2) = 1.0379908060... (End)
O.g.f.: Sum_{n >= 1} mu(n)*x^n*(1 + 26*x^n + 66*x^(2*n) + 26*x^(3*n) + x^(4*n))/(1 - x^n)^6 = x + 31*x^2 + 242*x^3 + 992*x^4 + 3124*x^5 + .... - Peter Bala, Jan 31 2022
From Peter Bala, Jan 01 2024: (Start)
a(n) = Sum_{d divides n} d * J_4(d) * J_1(n/d) = Sum_{d divides n} d^2 * J_3(d) * J_2(n/d) = Sum_{d divides n} d^3 * J_2(d) * J_3(n/d) = Sum_{d divides n} d^4 * J_1(d) * J_4(n/d), where J_1(n) = phi(n) = A000010(n), J_2(n) = A007434(n), J(3,n) = A059376(n) and J_4(n) = A059377(n).
a(n) = Sum_{k = 1..n} gcd(k, n) * J_4(gcd(k, n)).
a(n) = Sum_{1 <= j, k <= n} gcd(j, k, n)^2 * J_3(gcd(j, k, n)). (End)
a(n) = Sum_{1 <= i, j <= n, lcm(i, j) = n} J_2(i) * J_3(j) = Sum_{1 <= i, j <= n, lcm(i, j) = n} phi(i) * J_4(j) (apply Lehmer, Theorem 1). - Peter Bala, Jan 30 2024

A069091 Jordan function J_6(n).

Original entry on oeis.org

1, 63, 728, 4032, 15624, 45864, 117648, 258048, 530712, 984312, 1771560, 2935296, 4826808, 7411824, 11374272, 16515072, 24137568, 33434856, 47045880, 62995968, 85647744, 111608280, 148035888, 187858944, 244125000, 304088904, 386889048
Offset: 1

Views

Author

Benoit Cloitre, Apr 05 2002

Keywords

Comments

Moebius transform of n^6. - Enrique Pérez Herrero, Sep 14 2010
a(n) is divisible by 504 = (2^3)*(3^3)*7 = A006863(3) except for n = 1, 2, 3 and 7. See Lugo. - Peter Bala, Jan 13 2024

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 199, #3.

Crossrefs

Cf. A059379 and A059380 (triangle of values of J_k(n)), A000010 (J_1), A007434 (J_2), A059376 (J_3), A059377 (J_4), A059378 (J_5), A069092 - A069095 (J_7 through J_10).
Cf. A065959.
Cf. A013665.

Programs

  • Maple
    with(numtheory): seq(add(d^6 * mobius(n/d), d in divisors(n)), n = 1..100); # Peter Bala, Jan 13 2024
  • Mathematica
    JordanTotient[n_,k_:1]:=DivisorSum[n,#^k*MoebiusMu[n/# ]&]/;(n>0)&&IntegerQ[n]
    A069091[n_IntegerQ]:=JordanTotient[n,6]; (* Enrique Pérez Herrero, Sep 14 2010 *)
    f[p_, e_] := p^(6*e) - p^(6*(e-1)); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Oct 12 2020 *)
  • PARI
    for(n=1,100,print1(sumdiv(n,d,d^6*moebius(n/d)),","))

Formula

a(n) = Sum_{d|n} d^6*mu(n/d).
Multiplicative with a(p^e) = p^(6e)-p^(6(e-1)).
Dirichlet generating function: zeta(s-6)/zeta(s). - Ralf Stephan, Jul 04 2013
a(n) = n^6*Product_{distinct primes p dividing n} (1-1/p^6). - Tom Edgar, Jan 09 2015
Sum_{k=1..n} a(k) ~ n^7 / (7*zeta(7)). - Vaclav Kotesovec, Feb 07 2019
From Amiram Eldar, Oct 12 2020: (Start)
Limit_{n->oo} (1/n) * Sum_{k=1..n} a(k)/k^6 = 1/zeta(7).
Sum_{n>=1} 1/a(n) = Product_{p prime} (1 + p^6/(p^6-1)^2) = 1.0175973008... (End)
O.g.f.: Sum_{n >= 1} mu(n)*A(x^n)/(1 - x^n)^7 = x + 63*x^2 + 728*x^3 + 4032*x^4 + 15624*x^5 + ..., where A(x) = x + 57*x^2 + 302*x^3 + 302*x^4 + 57*x^5 + x^6 is the 6th Eulerian polynomial. See A008292. - Peter Bala, Jan 31 2022

A351262 a(n) = n^10 * Sum_{p|n, p prime} 1/p^10.

Original entry on oeis.org

0, 1, 1, 1024, 1, 60073, 1, 1048576, 59049, 9766649, 1, 61514752, 1, 282476273, 9824674, 1073741824, 1, 3547250577, 1, 10001048576, 282534298, 25937425625, 1, 62991106048, 9765625, 137858492873, 3486784401, 289255703552, 1, 586710856801, 1, 1099511627776, 25937483650
Offset: 1

Views

Author

Wesley Ivan Hurt, Feb 05 2022

Keywords

Comments

Dirichlet convolution of A010051(n) and n^10. - Wesley Ivan Hurt, Jul 15 2025

Examples

			a(6) = 60073; a(6) = 6^10 * Sum_{p|6, p prime} 1/p^10 = 60466176 * (1/2^10 + 1/3^10) = 60073.
		

Crossrefs

Sequences of the form n^k * Sum_{p|n, p prime} 1/p^k for k = 0..10: A001221 (k=0), A069359 (k=1), A322078 (k=2), A351242 (k=3), A351244 (k=4), A351245 (k=5), A351246 (k=6), A351247 (k=7), A351248 (k=8), A351249 (k=9), this sequence (k=10).

Programs

  • Maple
    f:= proc(n) local p;
      n^10 * add(1/p^10, p = numtheory:-factorset(n))
    end proc:
    map(f, [$1..40]); # Robert Israel, Sep 10 2024
  • Mathematica
    Join[{0},Table[n^10 Total[1/FactorInteger[n][[;;,1]]^10],{n,2,40}]] (* Harvey P. Dale, Aug 10 2024 *)
  • PARI
    a(n) = my(f=factor(n)); n^10*sum(k=1, #f~, 1/f[k,1]^10); \\ Michel Marcus, Sep 10 2024
  • Python
    from sympy import primefactors
    def A351262(n): return sum((n//p)**10 for p in primefactors(n)) # Chai Wah Wu, Feb 05 2022
    

Formula

a(A000040(n)) = 1.
a(n) = Sum_{d|n} A069095(d)*A001221(n/d). - Ridouane Oudra, Jul 15 2025
From Wesley Ivan Hurt, Jul 15 2025: (Start)
a(n) = Sum_{d|n} c(d) * (n/d)^10, where c = A010051.
a(p^k) = p^(10*k-10) for p prime and k>=1. (End)

A351300 a(n) = n^5 * Product_{p|n, p prime} (1 + 1/p^5).

Original entry on oeis.org

1, 33, 244, 1056, 3126, 8052, 16808, 33792, 59292, 103158, 161052, 257664, 371294, 554664, 762744, 1081344, 1419858, 1956636, 2476100, 3301056, 4101152, 5314716, 6436344, 8245248, 9768750, 12252702, 14407956, 17749248, 20511150, 25170552, 28629152, 34603008, 39296688
Offset: 1

Views

Author

Wesley Ivan Hurt, Feb 06 2022

Keywords

Comments

Sum of the 5th 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), this sequence (k=5), A351301 (k=6), A351302 (k=7), A351303 (k=8), A351304 (k=9), A351305 (k=10).

Programs

  • Mathematica
    f[p_, e_] := p^(5*e) + p^(5*(e-1)); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 40] (* Amiram Eldar, Feb 08 2022 *)
  • PARI
    a(n)=sumdiv(n, d, moebius(n/d)^2*d^5);
    
  • PARI
    for(n=1, 100, print1(direuler(p=2, n, (1 + X)/(1 - p^5*X))[n], ", ")) \\ Vaclav Kotesovec, Feb 12 2022

Formula

a(n) = Sum_{d|n} d^5 * mu(n/d)^2.
a(n) = n^5 * Sum_{d|n} mu(d)^2 / d^5.
Multiplicative with a(p^e) = p^(5*e) + p^(5*e-5). - Sebastian Karlsson, Feb 08 2022
From Vaclav Kotesovec, Feb 12 2022: (Start)
Dirichlet g.f.: zeta(s)*zeta(s-5)/zeta(2*s).
Sum_{k=1..n} a(k) ~ n^6 * zeta(6) / (6 * zeta(12)) = 225225 * n^6 / (1382 * Pi^6).
Sum_{k>=1} 1/a(k) = Product_{primes p} (1 + p^5/(p^10-1)) = 1.03592823428850098309076014982275428113698561633329794485946580153004... (End)
a(n) = J_10(n) / J_5(n) = A069095(n) / A059378(n), where J_k is the k-th Jordan totient function. - Enrique Pérez Herrero, Nov 13 2022

A069093 Jordan function J_8(n).

Original entry on oeis.org

1, 255, 6560, 65280, 390624, 1672800, 5764800, 16711680, 43040160, 99609120, 214358880, 428236800, 815730720, 1470024000, 2562493440, 4278190080, 6975757440, 10975240800, 16983563040, 25499934720, 37817088000
Offset: 1

Views

Author

Benoit Cloitre, Apr 05 2002

Keywords

Comments

a(n) is divisible by 480 = (2^5)*3*5 = A006863(4), except for n = 1, 2, 3 and 5. See Lugo. - Peter Bala, Jan 13 2024

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 199, #3.

Crossrefs

Cf. A059379 and A059380 (triangle of values of J_k(n)), A000010 (J_1), A007434 (J_2), A059376 (J_3), A059377 (J_4), A059378 (J_5), A069091 - A069095 (J_6 through J_10)
Cf. A013667.

Programs

  • Maple
    with(numtheory): seq(add(d^8 * mobius(n/d), d in divisors(n)), n = 1..100); # Peter Bala, Jan 13 2024
  • Mathematica
    JordanJ[n_, k_] := DivisorSum[n, #^k*MoebiusMu[n/#] &]; f[n_] := JordanJ[n, 8]; Array[f, 25]
    f[p_, e_] := p^(8*e) - p^(8*(e-1)); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Oct 12 2020 *)
  • PARI
    for(n=1,100,print1(sumdiv(n,d,d^8*moebius(n/d)),","))

Formula

a(n) = Sum_{d|n} d^8*mu(n/d).
Multiplicative with a(p^e) = p^(8e)-p^(8(e-1)).
Dirichlet generating function: zeta(s-8)/zeta(s). - Ralf Stephan, Jul 04 2013
a(n) = n^8*Product_{distinct primes p dividing n} (1-1/p^8). - Tom Edgar, Jan 09 2015
Sum_{k=1..n} a(k) ~ n^9 / (9*zeta(9)). - Vaclav Kotesovec, Feb 07 2019
From Amiram Eldar, Oct 12 2020: (Start)
Limit_{n->oo} (1/n) * Sum_{k=1..n} a(k)/k^8 = 1/zeta(9).
Sum_{n>=1} 1/a(n) = Product_{p prime} (1 + p^8/(p^8-1)^2) = 1.0040927606... (End)

A023002 Sum of 10th powers.

Original entry on oeis.org

0, 1, 1025, 60074, 1108650, 10874275, 71340451, 353815700, 1427557524, 4914341925, 14914341925, 40851766526, 102769130750, 240627622599, 529882277575, 1106532668200, 2206044295976, 4222038196425, 7792505423049, 13923571680850
Offset: 0

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Author

Keywords

Crossrefs

Sequences of the form Sum_{j=0..n} j^m : A000217 (m=1), A000330 (m=2), A000537 (m=3), A000538 (m=4), A000539 (m=5), A000540 (m=6), A000541 (m=7), A000542 (m=8), A007487 (m=9), this sequence (m=10), A123095 (m=11), A123094 (m=12), A181134 (m=13).
Row 10 of array A103438.

Programs

Formula

a(n) = n*(n+1)*(2*n+1)*(n^2+n-1)(3*n^6 +9*n^5 +2*n^4 -11*n^3 +3*n^2 +10*n -5)/66 (see MathWorld, Power Sum, formula 40). - Bruno Berselli, Apr 26 2010
a(n) = n*A007487(n) - Sum_{i=0..n-1} A007487(i). - Bruno Berselli, Apr 27 2010
From Bruno Berselli, Aug 23 2011: (Start)
a(n) = -a(-n-1).
G.f.: x*(1+x)*(1 +1012*x +46828*x^2 +408364*x^3 +901990*x^4 +408364*x^5 +46828*x^6 +1012*x^7 +x^8)/(1-x)^12. (End)
a(n) = (-1)*Sum_{j=1..10} j*Stirling1(n+1,n+1-j)*Stirling2(n+10-j,n). - Mircea Merca, Jan 25 2014
a(n) = Sum_{i=1..n} J_10(i)*floor(n/i), where J_10 is A069095. - Ridouane Oudra, Jul 17 2025

A069092 Jordan function J_7(n).

Original entry on oeis.org

1, 127, 2186, 16256, 78124, 277622, 823542, 2080768, 4780782, 9921748, 19487170, 35535616, 62748516, 104589834, 170779064, 266338304, 410338672, 607159314, 893871738, 1269983744, 1800262812, 2474870590, 3404825446, 4548558848
Offset: 1

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Author

Benoit Cloitre, Apr 05 2002

Keywords

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 199, #3.

Crossrefs

Cf. A059379 and A059380 (triangle of values of J_k(n)), A000010 (J_1), A059376 (J_3), A059377 (J_4), A059378 (J_5).
Cf. A069091 (J_6), A069092 (J_7), A069093 (J_8), A069094 (J_9), A069095 (J_10). [Enrique Pérez Herrero, Nov 02 2010]
Cf. A013666.

Programs

  • Mathematica
    JordanTotient[n_, k_: 1] := DivisorSum[n, (#^k)*MoebiusMu[n/# ] &] /; (n > 0) && IntegerQ[n]
    A069092[n_] := JordanTotient[n, 7]; (* Enrique Pérez Herrero, Nov 02 2010 *)
    f[p_, e_] := p^(7*e) - p^(7*(e-1)); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Oct 12 2020 *)
  • PARI
    for(n=1, 100, print1(sumdiv(n, d, d^7*moebius(n/d)), ", "))

Formula

a(n) = Sum_{d|n} d^7*mu(n/d).
Multiplicative with a(p^e) = p^(7e)-p^(7(e-1)).
Dirichlet generating function: zeta(s-7)/zeta(s). - Ralf Stephan, Jul 04 2013
a(n) = n^7*Product_{distinct primes p dividing n} (1-1/p^7). - Tom Edgar, Jan 09 2015
Sum_{k=1..n} a(k) ~ 4725*n^8 / (4*Pi^8). - Vaclav Kotesovec, Feb 07 2019
From Amiram Eldar, Oct 12 2020: (Start)
lim_{n->oo} (1/n) * Sum_{k=1..n} a(k)/k^7 = 1/zeta(8).
Sum_{n>=1} 1/a(n) = Product_{p prime} (1 + p^7/(p^7-1)^2) = 1.0084115178... (End)
O.g.f.: Sum_{n >= 1} mu(n)*A_7(x^n)/(1 - x^n)^8 = x + 127*x^2 + 2186*x^3 + 16256*x^4 + 78124*x^5 + ..., where A_7(x) = x + 120*x^2 + 1191*x^3 + 2416*x^4 + 1191*x^5 + 120*x^6 + x^7 is the 7th Eulerian polynomial. See A008292. - Peter Bala, Jan 31 2022

A160957 a(n) = Sum_{d|n} Moebius(n/d)*d^(b-1)/phi(n) for b = 11.

Original entry on oeis.org

1, 1023, 29524, 523776, 2441406, 30203052, 47079208, 268173312, 581120892, 2497558338, 2593742460, 15463962624, 11488207654, 48162029784, 72080070744, 137304735744, 125999618778, 594486672516, 340614792100, 1278749869056
Offset: 1

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Author

N. J. A. Sloane, Nov 19 2009

Keywords

Comments

a(n) is the number of lattices L in Z^10 such that the quotient group Z^10 / L is C_n. - Álvar Ibeas, Nov 26 2015

Crossrefs

Column 10 of A263950.

Programs

  • Mathematica
    b = 11; Table[Sum[MoebiusMu[n/d] d^(b - 1)/EulerPhi@ n, {d, Divisors@ n}], {n, 20}] (* Michael De Vlieger, Nov 27 2015 *)
    f[p_, e_] := p^(9*e - 9) * (p^10-1) / (p-1); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 25] (* Amiram Eldar, Nov 08 2022 *)
  • PARI
    vector(100, n, sumdiv(n^9, d, if(ispower(d, 10), moebius(sqrtnint(d, 10))*sigma(n^9/d), 0))) \\ Altug Alkan, Nov 26 2015
    
  • PARI
    a(n) = {my(f = factor(n)); prod(i = 1, #f~, (f[i,1]^10 - 1)*f[i,1]^(9*f[i,2] - 9)/(f[i,1] - 1));} \\ Amiram Eldar, Nov 08 2022

Formula

a(n) = A069095(n)/A000010(n). - R. J. Mathar, Jul 12 2011
From Álvar Ibeas, Nov 26 2015: (Start)
Multiplicative with a(p^e) = p^(9e-9) * (p^10-1) / (p-1).
For squarefree n, a(n) = A000203(n^9). (End)
From Amiram Eldar, Nov 08 2022: (Start)
Sum_{k=1..n} a(k) ~ c * n^10, where c = (1/10) * Product_{p prime} (1 + (p^9-1)/((p-1)*p^10)) = 0.1942316928... .
Sum_{k>=1} 1/a(k) = zeta(9)*zeta(10) * Product_{p prime} (1 - 2/p^10 + 1/p^19) = 1.0010137674... . (End)
a(n) = (1/n) * Sum_{d|n} mu(n/d)*sigma(d^10). - Ridouane Oudra, Apr 02 2025

Extensions

Definition corrected by Enrique Pérez Herrero, Oct 30 2010
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