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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A266556 Decimal expansion of the generalized Glaisher-Kinkelin constant A(9).

Original entry on oeis.org

1, 0, 1, 8, 4, 6, 9, 9, 2, 9, 9, 2, 0, 9, 9, 2, 9, 1, 2, 1, 7, 0, 6, 5, 9, 0, 4, 9, 3, 7, 6, 6, 7, 2, 1, 7, 2, 3, 0, 8, 6, 1, 0, 1, 9, 0, 5, 6, 4, 0, 7, 4, 9, 2, 0, 3, 8, 0, 0, 7, 0, 5, 7, 3, 6, 7, 5, 4, 7, 6, 1, 9, 4, 9, 4
Offset: 1

Views

Author

G. C. Greubel, Dec 31 2015

Keywords

Comments

Also known as the 9th Bendersky constant.

Examples

			1.018469929920992912170659049376672172308610190564074920380...
		

Crossrefs

Cf. A019727 (A(0)), A074962 (A(1)), A243262 (A(2)), A243263 (A(3)), A243264 (A(4)), A243265 (A(5)), A266553 (A(6)), A266554 (A(7)), A266555 (A(8)), A266556 (A(9)), A266557 (A(10)), A266558 (A(11)), A266559 (A(12)), A260662 (A(13)), A266560 (A(14)), A266562 (A(15)), A266563 (A(16)), A266564 (A(17)), A266565 (A(18)), A266566 (A(19)), A266567 (A(20)).

Programs

  • Mathematica
    Exp[N[(BernoulliB[10]/10)*(EulerGamma + Log[2*Pi] - Zeta'[10]/Zeta[10]), 200]]

Formula

A(k) = exp(H(k)*B(k+1)/(k+1) - zeta'(-k)), where B(k) is the k-th Bernoulli number, H(k) the k-th harmonic number, and zeta'(x) is the derivative of the Riemann zeta function.
A(9) = exp(H(9)*B(10)/10 - zeta'(-9)) = exp((B(10)/10)*(EulerGamma + log(2*Pi) - (zeta'(10)/zeta(10)))).
Equals (2*Pi*exp(gamma) * Product_{p prime} p^(1/(p^10-1)))^c, where gamma is Euler's constant (A001620), and c = Bernoulli(10)/10 = 1/132 (Van Gorder, 2012). - Amiram Eldar, Feb 08 2024

A266557 Decimal expansion of the generalized Glaisher-Kinkelin constant A(10).

Original entry on oeis.org

1, 0, 1, 9, 1, 1, 0, 2, 3, 3, 3, 2, 9, 3, 8, 3, 8, 5, 3, 7, 2, 2, 1, 6, 4, 7, 0, 4, 9, 8, 6, 2, 9, 7, 5, 1, 3, 5, 1, 3, 4, 8, 1, 3, 7, 2, 8, 4, 0, 9, 9, 6, 0, 4, 4, 5, 9, 6, 4, 1, 4, 9, 4, 6, 7, 6, 5, 5, 4, 2, 8, 9, 5, 9, 3
Offset: 1

Views

Author

G. C. Greubel, Dec 31 2015

Keywords

Comments

Also known as the 10th Bendersky constant.

Examples

			1.01911023332938385372216470498629751351348137284099604...
		

Crossrefs

Cf. A019727 (A(0)), A074962 (A(1)), A243262 (A(2)), A243263 (A(3)), A243264 (A(4)), A243265 (A(5)), A266553 (A(6)), A266554 (A(7)), A266555 (A(8)), A266556 (A(9)), A266558 (A(11)), A266559 (A(12)), A260662 (A(13)), A266560 (A(14)), A266562 (A(15)), A266563 (A(16)), A266564 (A(17)), A266565 (A(18)), A266566 (A(19)), A266567 (A(20)).

Programs

  • Mathematica
    Exp[N[(BernoulliB[10]/4)*(Zeta[11]/Zeta[10]), 200]]

Formula

A(k) = exp(H(k)*B(k+1)/(k+1) - zeta'(-k)), where B(k) is the k-th Bernoulli number, H(k) the k-th harmonic number, and zeta'(x) is the derivative of the Riemann zeta function.
A(10) = exp(-zeta'(-10)) = exp((B(10)/4)*(zeta(11)/zeta(10))).
A(10) = exp(10! * Zeta(11) / (2^11 * Pi^10)). - Vaclav Kotesovec, Jan 01 2016

A351272 Sum of the 9th powers of the squarefree divisors of n.

Original entry on oeis.org

1, 513, 19684, 513, 1953126, 10097892, 40353608, 513, 19684, 1001953638, 2357947692, 10097892, 10604499374, 20701400904, 38445332184, 513, 118587876498, 10097892, 322687697780, 1001953638, 794320419872, 1209627165996, 1801152661464, 10097892, 1953126, 5440108178862
Offset: 1

Views

Author

Wesley Ivan Hurt, Feb 05 2022

Keywords

Comments

Inverse Möbius transform of n^9 * mu(n)^2. - Wesley Ivan Hurt, Jun 08 2023

Examples

			a(4) = 513; a(4) = Sum_{d|4} d^9 * mu(d)^2 = 1^9*1 + 2^9*1 + 4^9*0 = 513.
		

Crossrefs

Cf. A008683 (mu), A013661, A013668.
Sum of the k-th powers of the squarefree divisors of n for k=0..10: A034444 (k=0), A048250 (k=1), A351265 (k=2), A351266 (k=3), A351267 (k=4), A351268 (k=5), A351269 (k=6), A351270 (k=7), A351271 (k=8), this sequence (k=9), A351273 (k=10).

Programs

  • Mathematica
    a[1] = 1; a[n_] := Times @@ (1 + FactorInteger[n][[;; , 1]]^9); Array[a, 100] (* Amiram Eldar, Feb 06 2022 *)
    Table[Total[Select[Divisors[n],SquareFreeQ]^9],{n,30}] (* Harvey P. Dale, Feb 21 2023 *)

Formula

a(n) = Sum_{d|n} d^9 * mu(d)^2.
Multiplicative with a(p^e) = 1 + p^9. - Amiram Eldar, Feb 06 2022
G.f.: Sum_{k>=1} mu(k)^2 * k^9 * x^k / (1 - x^k). - Ilya Gutkovskiy, Feb 06 2022
Sum_{k=1..n} a(k) ~ c * n^10, where c = zeta(10)/(10*zeta(2)) = Pi^8/155925 = 0.0608531... . - Amiram Eldar, Nov 10 2022

A351606 a(n) = n^8 * Sum_{d^2|n} 1 / d^8.

Original entry on oeis.org

1, 256, 6561, 65792, 390625, 1679616, 5764801, 16842752, 43053282, 100000000, 214358881, 431661312, 815730721, 1475789056, 2562890625, 4311810048, 6975757441, 11021640192, 16983563041, 25700000000, 37822859361, 54875873536, 78310985281, 110505295872, 152588281250
Offset: 1

Views

Author

Wesley Ivan Hurt, Feb 14 2022

Keywords

Crossrefs

Sequences of the form n^k * Sum_{d^2|n} 1/d^k for k = 0..10: A046951 (k=0), A340774 (k=1), A351600 (k=2), A351601 (k=3), A351602 (k=4), A351603 (k=5), A351604 (k=6), A351605 (k=7), this sequence (k=8), A351607 (k=9), A351608 (k=10).
Cf. A013668.

Programs

  • Mathematica
    f[p_, e_] := p^8*(p^(8*e) - p^(8*Floor[(e - 1)/2]))/(p^8 - 1); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 30] (* Amiram Eldar, Nov 13 2022 *)
  • PARI
    a(n) = n^8*sumdiv(n, d, if (issquare(d), 1/d^4)); \\ Michel Marcus, Feb 15 2022

Formula

Multiplicative with a(p^e) = p^8*(p^(8*e) - p^(8*floor((e-1)/2)))/(p^8 - 1). - Sebastian Karlsson, Feb 25 2022
Sum_{k=1..n} a(k) ~ c * n^9, where c = zeta(10)/9 = Pi^10/841995 = 0.1112216... . - Amiram Eldar, Nov 13 2022

A352037 Sum of the 9th powers of the odd proper divisors of n.

Original entry on oeis.org

0, 1, 1, 1, 1, 19684, 1, 1, 19684, 1953126, 1, 19684, 1, 40353608, 1972809, 1, 1, 387440173, 1, 1953126, 40373291, 2357947692, 1, 19684, 1953126, 10604499374, 387440173, 40353608, 1, 38445332184, 1, 1, 2357967375, 118587876498, 42306733, 387440173, 1, 322687697780
Offset: 1

Views

Author

Wesley Ivan Hurt, Mar 01 2022

Keywords

Examples

			a(10) = 1953126; a(10) = Sum_{d|10, d<10, d odd} d^9 = 1^9 + 5^9 = 1953126.
		

Crossrefs

Sum of the k-th powers of the odd proper divisors of n for k=0..10: A091954 (k=0), A091570 (k=1), A351647 (k=2), A352031 (k=3), A352032 (k=4), A352033 (k=5), A352034 (k=6), A352035 (k=7), A352036 (k=8), this sequence (k=9), A352038 (k=10).

Programs

  • Mathematica
    f[2, e_] := 1; f[p_, e_] := (p^(9*e+9) - 1)/(p^9 - 1); a[1] = 0; a[n_] := Times @@ f @@@ FactorInteger[n] - If[OddQ[n], n^9, 0]; Array[a, 60] (* Amiram Eldar, Oct 11 2023 *)

Formula

a(n) = Sum_{d|n, d
G.f.: Sum_{k>=1} (2*k-1)^9 * x^(4*k-2) / (1 - x^(2*k-1)). - Ilya Gutkovskiy, Mar 02 2022
From Amiram Eldar, Oct 11 2023: (Start)
a(n) = A321813(n) - n^9*A000035(n).
Sum_{k=1..n} a(k) ~ c * n^10, where c = (zeta(10)-1)/20 = 0.0000497287... . (End)

A352055 Sum of the 9th powers of the divisor complements of the odd proper divisors of n.

Original entry on oeis.org

0, 512, 19683, 262144, 1953125, 10078208, 40353607, 134217728, 387440172, 1000000512, 2357947691, 5160042496, 10604499373, 20661047296, 38445332183, 68719476736, 118587876497, 198369368576, 322687697779, 512000262144, 794320419871, 1207269218304, 1801152661463, 2641941757952
Offset: 1

Author

Wesley Ivan Hurt, Mar 01 2022

Keywords

Examples

			a(10) = 10^9 * Sum_{d|10, d<10, d odd} 1 / d^9 = 10^9 * (1/1^9 + 1/5^9) = 1000000512.
		

Crossrefs

Sum of the k-th powers of the divisor complements of the odd proper divisors of n for k=0..10: A091954 (k=0), A352047 (k=1), A352048 (k=2), A352049 (k=3), A352050 (k=4), A352051 (k=5), A352052 (k=6), A352053 (k=7), A352054 (k=8), this sequence (k=9), A352056 (k=10).

Programs

  • Mathematica
    A352055[n_]:=DivisorSum[n,1/#^9&,#A352055,50] (* Paolo Xausa, Aug 10 2023 *)
    a[n_] := DivisorSigma[-9, n/2^IntegerExponent[n, 2]] * n^9 - Mod[n, 2]; Array[a, 100] (* Amiram Eldar, Oct 13 2023 *)
  • PARI
    a(n) = n^9 * sigma(n >> valuation(n, 2), -9) - n % 2; \\ Amiram Eldar, Oct 13 2023

Formula

a(n) = n^9 * Sum_{d|n, d
G.f.: Sum_{k>=2} k^9 * x^k / (1 - x^(2*k)). - Ilya Gutkovskiy, May 19 2023
From Amiram Eldar, Oct 13 2023: (Start)
a(n) = A321813(n) * A006519(n)^9 - A000035(n).
Sum_{k=1..n} a(k) = c * n^10 / 10, where c = 1023*zeta(10)/1024 = 1.0000170413... . (End)

A293904 Decimal expansion of zeta(21).

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 4, 7, 6, 9, 3, 2, 9, 8, 6, 7, 8, 7, 8, 0, 6, 4, 6, 3, 1, 1, 6, 7, 1, 9, 6, 0, 4, 3, 7, 3, 0, 4, 5, 9, 6, 6, 4, 4, 6, 6, 9, 4, 7, 8, 4, 9, 3, 7, 6, 0, 0, 2, 0, 7, 4, 8, 7, 3, 7, 6, 5, 9, 6, 8, 3, 9, 0, 8, 7, 8, 9, 8, 1, 5, 9, 8, 3, 3, 8, 7, 6, 6
Offset: 1

Author

Frank Ellermann, Oct 19 2017

Keywords

Comments

Web searches find 1.0000004769329867878 in Python tools. Simon Plouffe published 1000 digits for zeta(9) up to zeta(2051) many years ago.

Examples

			1.000000476932986787806...
		

Programs

  • Mathematica
    RealDigits[Zeta[21], 10, 100][[1]] (* Amiram Eldar, May 31 2021 *)

A354600 a(n) = Product_{k=0..9} floor((n+k)/10).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 1536, 2304, 3456, 5184, 7776, 11664, 17496, 26244, 39366, 59049, 78732, 104976, 139968, 186624, 248832, 331776, 442368, 589824, 786432, 1048576, 1310720, 1638400, 2048000, 2560000, 3200000, 4000000
Offset: 0

Author

Wesley Ivan Hurt, Jul 08 2022

Keywords

Comments

For n >= 10, a(n) is the maximal product of ten positive integers with sum n.

Crossrefs

Maximal product of k positive integers with sum n, for k = 2..10: A002620 (k=2), A006501 (k=3), A008233 (k=4), A008382 (k=5), A008881 (k=6), A009641 (k=7), A009694 (k=8), A009714 (k=9), this sequence (k=10).
Cf. A008454 (subsequence), A013668.

Programs

  • Mathematica
    Table[Product[Floor[(n + k)/10], {k, 0, 9}], {n, 0, 50}]
  • PARI
    a(n) = prod(k=0, 9, (n+k)\10); \\ Michel Marcus, Jul 09 2022

Formula

a(n) = 2*a(n-1) - a(n-2) + 9*a(n-10) - 18*a(n-11) + 9*a(n-12) - 36*a(n-20) + 72*a(n-21) - 36*a(n-22) + 84*a(n-30) - 168*a(n-31) + 84*a(n-32) - 126*a(n-40) + 252*a(n-41) - 126*a(n-42) + 126*a(n-50) - 252*a(n-51) + 126*a(n-52) - 84*a(n-60) + 168*a(n-61) - 84*a(n-62) + 36*a(n-70) - 72*a(n-71) + 36*a(n-72) - 9*a(n-80) + 18*a(n-81) - 9*a(n-82) + a(n-90) - 2*a(n-91) + a(n-92).
Sum_{n>=10} 1/a(n) = 1 + zeta(10). - Amiram Eldar, Jan 10 2023
a(10*n) = n^10 (A008454). - Bernard Schott, Feb 02 2023

A069094 Jordan function J_9(n).

Original entry on oeis.org

1, 511, 19682, 261632, 1953124, 10057502, 40353606, 133955584, 387400806, 998046364, 2357947690, 5149441024, 10604499372, 20620692666, 38441386568, 68585259008, 118587876496, 197961811866, 322687697778, 510999738368
Offset: 1

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. A013668.

Programs

  • Mathematica
    JordanJ[n_, k_] := DivisorSum[n, #^k*MoebiusMu[n/#] &]; f[n_] := JordanJ[n, 9]; Array[f, 22]
    f[p_, e_] := p^(9*e) - p^(9*(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^9*moebius(n/d)),","))

Formula

a(n) = Sum_{d|n} d^9*mu(n/d).
Multiplicative with a(p^e) = p^(9e)-p^(9(e-1)).
Dirichlet generating function: zeta(s-9)/zeta(s). - Ralf Stephan, Jul 04 2013
a(n) = n^9*Product_{distinct primes p dividing n} (1-1/p^9). - Tom Edgar, Jan 09 2015
Sum_{k=1..n} a(k) ~ 18711*n^10 / (2*Pi^10). - Vaclav Kotesovec, Feb 07 2019
From Amiram Eldar, Oct 12 2020: (Start)
lim_{n->oo} (1/n) * Sum_{k=1..n} a(k)/k^9 = 1/zeta(10).
Sum_{n>=1} 1/a(n) = Product_{p prime} (1 + p^9/(p^9-1)^2) = 1.0020122252... (End)

A096962 a(n) = Sum_{0

Original entry on oeis.org

1, 512, 19684, 262144, 1953126, 10078208, 40353608, 134217728, 387440173, 1000000512, 2357947692, 5160042496, 10604499374, 20661047296, 38445332184, 68719476736, 118587876498, 198369368576, 322687697780, 512000262144
Offset: 1

Author

Ralf Stephan, Jul 18 2004

Keywords

Examples

			G.f. = q + 512*q^2 + 19684*q^3 + 262144*q^4 + 1953126*q^5 + 10078208*q^6 + ...
		

Crossrefs

Programs

  • Magma
    A := Basis( ModularForms( Gamma0(2), 10), 21); A[2] + 512*A[3]; /* Michael Somos, Aug 25 2014 */
  • Mathematica
    a[ n_] := If[ n < 1, 0, Sum[ d^9 Boole[ OddQ[ n/d]], {d, Divisors[ n]}]]; (* Michael Somos, Jun 04 2013 *)
    a[ n_] := SeriesCoefficient[ With[{u1 = QPochhammer[ q]^8, u2 = QPochhammer[ q^2]^4, u4 = QPochhammer[ q^4]^8}, q u2 (u1 + 32 q u4) (u1^2 + 496 q u4 u1 + 7936 q^2 u4^2 ) / u1], {q, 0, n}]; (* Michael Somos, Jun 04 2013 *)
  • PARI
    {a(n) = if( n<1, 0, sumdiv( n, d, (n/d%2) * d^9))}; /* Michael Somos, Jun 04 2013 */
    
  • PARI
    {a(n) = local(A, A1, A2, A4); if( n<1, 0, n--; A = x * O(x^n); A1 = eta(x + A)^8; A2 = eta(x^2 + A)^4; A4 = eta(x^4 + A)^8; polcoeff( A2 * (A1 + 32*x * A4) * (A1^2 + 496*x * A1*A4 + 7936*x^2 * A4^2) / A1, n))}; /* Michael Somos, Jun 04 2013 */
    
  • Sage
    ModularForms( Gamma0(2), 10, prec=33).2; # Michael Somos, Jun 04 2013
    

Formula

G.f.: Sum_{k>0} k^9 * x^k / (1 - x^(2*k)).
From Amiram Eldar, Nov 02 2022: (Start)
Multiplicative with a(2^e) = 2^(9*e) and a(p^e) = (p^(9*e+9)-1)/(p^9-1) for p > 2.
Sum_{k=1..n} a(k) ~ c * n^10, where c = 1023*zeta(10)/10240 = 31*Pi^10/29030400 = 0.100001704136... . (End)
Dirichlet g.f.: zeta(s)*zeta(s-9)*(1-1/2^s). - Amiram Eldar, Jan 09 2023
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