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 1-7 of 7 results.

A001014 Sixth powers: a(n) = n^6.

Original entry on oeis.org

0, 1, 64, 729, 4096, 15625, 46656, 117649, 262144, 531441, 1000000, 1771561, 2985984, 4826809, 7529536, 11390625, 16777216, 24137569, 34012224, 47045881, 64000000, 85766121, 113379904, 148035889, 191102976, 244140625, 308915776, 387420489, 481890304
Offset: 0

Views

Author

Keywords

Comments

Numbers both square and cubic. - Patrick De Geest
Totally multiplicative sequence with a(p) = p^6 for prime p. - Jaroslav Krizek, Nov 01 2009
Numbers n for which the order of the torsion subgroup of the elliptic curve y^2 = x^3 + n is t = 6, cf. Gebel link. - Artur Jasinski, Jun 30 2010
Note that Sum_{n>=1} 1/a(n) = Pi^6 / 945. - Mohammad K. Azarian, Nov 01 2011
The binomial transform yields A056468. The inverse binomial transform yields the (finite) 0, 1, 62, 540, ..., 720, the 6th row in A019538 and A131689. - R. J. Mathar, Jan 16 2013
For n > 0, a(n) is the largest number k such that k + n^3 divides k^2 + n^3. - Derek Orr, Oct 01 2014

Examples

			The 6th powers of the first few integers are: 0^6 = 0 = a(0), 1^6 = 1 = a(1), 2^6 = 64 = a(2), 3^6 = 9^3 = 729 = a(3), 4^6 = 2^12 = 4096 = a(4), 5^6 = 25^3 = 15625 = a(5), etc.
		

References

  • R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics. Addison-Wesley, Reading, MA, 1990, p. 255; 2nd. ed., p. 269. Worpitzky's identity, eq. (6.37).
  • Granino A. Korn and Theresa M.Korn, Mathematical Handbook for Scientists and Engineers, McGraw-Hill Book Company, New York (1968), p. 982.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Subsequence of A201217.
Cf. A000540 (partial sums), A022522 (first differences), A008292.
Intersection of A000290 (squares) and A000578 (cubes).
Cf. A002604 (n^6+1), A123866 (n^6-1), A013664 (zeta(6)), A275703 (eta(6)).
Cf. A003358 - A003368 (sums of 2, ..., 12 positive sixth powers).

Programs

Formula

a(n) = A123866(n) + 1 = A002604(n) - 1.
G.f.: -x*(1+x)*(x^4+56*x^3+246*x^2+56*x+1) / (x-1)^7. - Simon Plouffe in his 1992 dissertation
Multiplicative with a(p^e) = p^(6e). - David W. Wilson, Aug 01 2001
E.g.f.: (x + 31x^2 + 90x^3 + 65x^4 + 15x^5 + x^6)*exp(x). Generally, the e.g.f. for n^m is Sum_{k=1..m} A008277(m,k)*x^k*exp(x). - Geoffrey Critzer, Aug 25 2013
From Ant King, Sep 23 2013: (Start)
Signature {7, -21, 35, -35, 21, -7, 1}.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) + 720. (End)
a(n) == 1 (mod 7) if gcd(n, 7) = 1, otherwise a(n) == 0 (mod 7). See A109720. - Jake Lawrence, May 28 2016
From Ilya Gutkovskiy, Jul 06 2016: (Start)
Dirichlet g.f.: zeta(s-6).
Sum_{n>=1} 1/a(n) = Pi^6/945 = A013664. (End)
a(n) = Sum_{k=1..6} Eulerian(6, k)*binomial(n+6-k, 6), with Eulerian(6, k) = A008292(6, k) (the numbers are 1, 57, 302, 302, 57, 1) for n >= 0. Worpitzki's identity for powers of 6. See. e.g., Graham et al., eq. (6, 37) (using A173018, the row reversed version of A123125). - Wolfdieter Lang, Jul 17 2019
Sum_{n>=1} (-1)^(n+1)/a(n) = 31*zeta(6)/32 = 31*Pi^6/30240 (A275703). - Amiram Eldar, Oct 08 2020
From Amiram Eldar, Jan 20 2021: (Start)
Product_{n>=1} (1 + 1/a(n)) = (cosh(Pi)-cos(sqrt(3)*Pi))*sinh(Pi)/(2*Pi^3).
Product_{n>=2} (1 - 1/a(n)) = cosh(sqrt(3)*Pi/2)^2/(6*Pi^2). (End)

Extensions

Comments from 2010 - 2011 edited by M. F. Hasler, Jul 05 2024

A136677 Numerator of Sum_{k=1..n} (-1)^(k+1)/k^6.

Original entry on oeis.org

1, 63, 45991, 2942695, 45982595359, 5109066151, 601081707598999, 38469080386820311, 252396118308232060471, 252395862211967012407, 447134922152359540530757327, 447134770212444455649757327, 2158234586764514215343657417779543, 308319185132349039219686748825649
Offset: 1

Views

Author

Alexander Adamchuk, Jan 16 2008

Keywords

Comments

p divides a(p-1) for prime p > 2. a(n) is prime for n = {19, 47, 164, ...} = A136686.
Lim_{n -> infinity} a(n)/A334605(n) = A275703 = (31/32)*A013664. - Petros Hadjicostas, May 07 2020

Examples

			The first few fractions are 1, 63/64, 45991/46656, 2942695/2985984, 45982595359/46656000000, 5109066151/5184000000, ... = a(n)/A334605(n). - _Petros Hadjicostas_, May 07 2020
		

Crossrefs

Programs

  • Mathematica
    Table[ Numerator[ Sum[ (-1)^(k+1)/k^6, {k,1,n} ] ], {n,1,30} ]
    Accumulate[Table[(-1)^(k+1)/k^6,{k,20}]]//Numerator (* Harvey P. Dale, Aug 21 2023 *)

A275710 Decimal expansion of the Dirichlet eta function at 7.

Original entry on oeis.org

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

Views

Author

Terry D. Grant, Aug 06 2016

Keywords

Examples

			0.99259381992283028267...
		

Crossrefs

Cf. A002162 (value at 1), A013665, A072691 (value at 2), A197070 (value at 3), A267315 (value at 4), A267316 (value at 5), A275703 (value at 6), A334668, A334669, A347150, A347059.

Programs

  • Mathematica
    RealDigits[63 Zeta[7]/64, 10, 100] [[1]]
  • PARI
    -polylog(7, -1) \\ Michel Marcus, Aug 20 2021
  • Sage
    s = RLF(0); s
    RealField(110)(s)
    for i in range(1, 10000): s -= (-1)^i / i^7
    print(s) # Terry D. Grant, Aug 06 2016
    

Formula

eta(7) = 63*zeta(7)/64 = (63*A013665)/64.
eta(7) = Lim_{n -> infinity} A334668(n)/A334669(n). - Petros Hadjicostas, May 07 2020
Equals Sum_{k>=1} (-1)^(k+1) / k^7. - Sean A. Irvine, Aug 19 2021

A334605 Denominator of Sum_{k=1..n} (-1)^(k+1)/k^6.

Original entry on oeis.org

1, 64, 46656, 2985984, 46656000000, 5184000000, 609892416000000, 39033114624000000, 256096265048064000000, 256096265048064000000, 453690155404813307904000000, 453690155404813307904000000, 2189875725319351517910798336000000
Offset: 1

Views

Author

Petros Hadjicostas, May 07 2020

Keywords

Comments

Lim_{n -> infinity} A136677(n)/a(n) = A275703 = (31/32)*A013664.

Examples

			The first few fractions are: 1, 63/64, 45991/46656, 2942695/2985984, 45982595359/46656000000, 5109066151/5184000000, ... = A136677/A334605.
		

Crossrefs

Cf. A013664, A136677 (numerators), A275703.

Programs

  • Mathematica
    Denominator @ Accumulate[Table[(-1)^(k + 1)/k^6, {k, 1, 13}]] (* Amiram Eldar, May 07 2020 *)
  • PARI
    a(n) = denominator(sum(k=1, n, (-1)^(k+1)/k^6)); \\ Michel Marcus, May 07 2020

A347059 Decimal expansion of the Dirichlet eta function at 9.

Original entry on oeis.org

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

Views

Author

Sean A. Irvine, Aug 14 2021

Keywords

Examples

			0.998094297541605330767783031852597950...
		

References

  • L. B. W. Jolley, Summation of Series, Dover, 1961, Eq. (306).

Crossrefs

Programs

  • Mathematica
    First[RealDigits[N[DirichletEta[9],87]]] (* Stefano Spezia, Aug 15 2021 *)
  • PARI
    -polylog(9, -1) \\ Michel Marcus, Aug 15 2021

Formula

Equals (255/256) * zeta(9).
Equals Sum_{k>=1} (-1)^(k+1) / k^9.
Equals eta(9).

A347150 Decimal expansion of the Dirichlet eta function at 8.

Original entry on oeis.org

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

Views

Author

Sean A. Irvine, Aug 19 2021

Keywords

Examples

			0.9962330018526478992272892600828036178741251594728980...
		

References

  • L. B. W. Jolley, Summation of Series, Dover, 1961, Eq. (306).

Crossrefs

Programs

  • Mathematica
    RealDigits[DirichletEta[8], 10, 100][[1]] (* Amiram Eldar, Aug 20 2021 *)
  • PARI
    -polylog(8, -1) \\ Michel Marcus, Aug 20 2021

Formula

Equals (127/128) * zeta(8).
Equals 127 * Pi^8 / 1209600.
Equals Sum_{k>=1} (-1)^(k+1) / k^8.
Equals eta(8).

A346927 Decimal expansion of the Dirichlet eta function at 10.

Original entry on oeis.org

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

Views

Author

Sean A. Irvine, Aug 07 2021

Keywords

Examples

			0.999039507598271565639221845699341831425929649666890...
		

References

  • L. B. W. Jolley, Summation of Series, Dover, 1961, Eq. (306).

Crossrefs

Programs

  • Mathematica
    RealDigits[DirichletEta[10], 10, 100][[1]] (* Amiram Eldar, Aug 08 2021 *)
  • PARI
    -polylog(10, -1) \\ Michel Marcus, Aug 08 2021

Formula

Equals 73 * Pi^10 / (2^9 * 3^5 * 5 * 11).
Equals (511/512) * zeta(10).
Equals Sum_{k>=1} (-1)^(k+1) / k^10.
Equals eta(10).
Showing 1-7 of 7 results.