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 10 results.

A097195 Expansion of s(12)^3*s(18)^2/(s(6)^2*s(36)), where s(k) = eta(q^k) and eta(q) is Dedekind's function, cf. A010815. Then replace q^6 with q.

Original entry on oeis.org

1, 2, 2, 2, 1, 2, 2, 2, 3, 0, 2, 2, 2, 2, 0, 4, 2, 2, 2, 0, 1, 2, 4, 2, 0, 2, 2, 2, 3, 2, 2, 0, 2, 2, 0, 2, 4, 2, 2, 0, 2, 4, 0, 4, 0, 2, 2, 2, 1, 0, 4, 2, 2, 0, 2, 2, 2, 4, 2, 0, 3, 2, 2, 2, 0, 0, 2, 4, 2, 0, 2, 4, 2, 2, 0, 0, 2, 2, 4, 2, 4, 2, 0, 2, 0, 4, 0, 2, 1, 0, 2, 2, 4
Offset: 0

Views

Author

N. J. A. Sloane, Sep 16 2004

Keywords

Examples

			G.f. = 1 + 2*x + 2*x^2 + 2*x^3 + x^4 + 2*x^5 + 2*x^6 + 2*x^7 + 3*x^8 + ...
G.f. = q + 2*q^7 + 2*q^13 + 2*q^19 + q^25 + 2*q^31 + 2*q^37 + 2*q^43 + ...
		

References

  • Nathan J. Fine, Basic Hypergeometric Series and Applications, Amer. Math. Soc., 1988; p. 80, Eq. (32.38).

Crossrefs

Programs

  • Mathematica
    a[n_] := DivisorSum[6n+1, KroneckerSymbol[-3, #]&]; Table[a[n], {n, 0, 100} ] (* Jean-François Alcover, Nov 23 2015, after Michael Somos *)
    QP = QPochhammer; s = QP[q^2]^3*(QP[q^3]^2/QP[q]^2/QP[q^6]) + O[q]^105; CoefficientList[s, q] (* Jean-François Alcover, Nov 27 2015 *)
    a[ n_] := If[ n < 1, Boole[n == 0], Times @@ (Which[# < 2, 0^#2, Mod[#, 6] == 5, 1 - Mod[#2, 2], True, #2 + 1] & @@@ FactorInteger@(6 n + 1))]; (* Michael Somos, Mar 05 2016 *)
  • PARI
    {a(n) = if( n<0, 0, sumdiv(6*n+1, d, kronecker(-3, d)))}; /* Michael Somos, Nov 03 2005 */
    
  • PARI
    {a(n) = my(A, p, e); if( n<0, 0, n = 6*n+1; A = factor(n); prod(k=1, matsize(A)[1], [p, e] = A[k, ]; if( p>3, if( p%6==1, e+1, !(e%2)))))}; /* Michael Somos, Nov 03 2005 */
    
  • PARI
    {a(n) = my(A); if( n<0, 0, A = x * O(x^n); polcoeff( eta(x^2 + A)^3 * eta(x^3 + A)^2 / (eta(x + A)^2 * eta(x^6 + A)), n))}; /* Michael Somos, Nov 03 2005 */

Formula

Fine gives an explicit formula for a(n) in terms of the divisors of n.
a(n) = b(6*n + 1) where b() is multiplicative with b(2^e) = b(3^e) = 0^e, b(p^e) = e+1 if p == 1 (mod 6), b(p^e) = (1 + (-1)^e)/2 if p == 5 (mod 6).
From Michael Somos, Nov 03 2005: (Start)
G.f.: Sum_{k in Z} x^k / (1 - x^(6*k + 1)).
G.f.: Sum_{k>=0} a(k) * x^(6*k + 1) = Sum_{k>0} x^(2*k-1) * (1 - x^(4*k - 2)) * (1 - x^(8*k - 4)) * (1 - x^(20*k - 10)) / (1 - x^(36*k - 18)). (End)
From Michael Somos, Mar 05 2016: (Start)
Expansion of q^(-1/6) * eta(q^2)^3 * eta(q^3)^2 / (eta(q)^2 * eta(q^6)) in powers of q.
Euler transform of period 6 sequence [ 2, -1, 0, -1, 2, -2, ...].
6 * a(n) = A004016(6*n + 1). (End)
Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Pi/sqrt(3) = 1.813799... (A093602). - Amiram Eldar, Nov 24 2023

A055101 Expansion of square of continued fraction 1/ ( 1+q/ ( 1+q^2/ ( 1+q^3/ ( 1+q^4/... )))).

Original entry on oeis.org

1, -2, 3, -2, -1, 4, -6, 6, -3, -2, 9, -16, 17, -10, -5, 24, -36, 36, -21, -10, 46, -74, 77, -42, -22, 94, -144, 142, -78, -38, 172, -266, 266, -146, -73, 312, -471, 464, -251, -122, 534, -814, 801, -432, -213, 910, -1364, 1328, -713, -344, 1485, -2234, 2178
Offset: 0

Views

Author

N. J. A. Sloane, Jun 14 2000

Keywords

Crossrefs

Product_{k>0} ((1-x^{5k-1}) * (1-x^{5k-4})/((1-x^{5k-2}) * (1-x^{5k-3})))^m: A285444 (m=-4), A285443 (m=-3), A285442 (m=-2), A003823 (m=-1), A007325 (m=1), this sequence (m=2), A055102 (m=3), A055103 (m=4).

Formula

a(0) = 1, a(n) = -(2/n)*Sum_{k=1..n} A109091(k)*a(n-k) for n > 0. - Seiichi Manyama, Apr 16 2017
Euler transform of period 5 sequence [-2, 2, 2, -2, 0, ...]. - Georg Fischer, Aug 18 2020
From Seiichi Manyama, Jul 29 2024: (Start)
G.f.: ( Sum_{k in Z} x^(3*k) / (1 - x^(5*k+1)) ) / ( Sum_{k in Z} x^k / (1 - x^(5*k+1)) ).
G.f.: ( Sum_{k in Z} x^(2*k) / (1 - x^(5*k+2)) ) / ( Sum_{k in Z} x^k / (1 - x^(5*k+2)) ). (End)

Extensions

More terms from Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), Jun 20 2000

A055102 Expansion of cube of continued fraction 1/ ( 1+q/ ( 1+q^2/ ( 1+q^3/ ( 1+q^4/... )))).

Original entry on oeis.org

1, -3, 6, -7, 3, 6, -17, 24, -21, 6, 21, -54, 77, -72, 24, 64, -159, 216, -190, 57, 159, -392, 534, -468, 144, 381, -924, 1220, -1044, 312, 833, -1992, 2625, -2244, 669, 1746, -4138, 5382, -4530, 1332, 3474, -8184, 10591, -8886, 2607, 6724, -15711
Offset: 0

Views

Author

N. J. A. Sloane, Jun 14 2000

Keywords

Crossrefs

Product_{k>0} ((1-x^{5k-1}) * (1-x^{5k-4})/((1-x^{5k-2}) * (1-x^{5k-3})))^m: A285444 (m=-4), A285443 (m=-3), A285442 (m=-2), A003823 (m=-1), A007325 (m=1), A055101 (m=2), this sequence (m=3), A055103 (m=4).

Formula

a(0) = 1, a(n) = -(3/n)*Sum_{k=1..n} A109091(k)*a(n-k) for n > 0. - Seiichi Manyama, Apr 16 2017
G.f.: ( Sum_{k in Z} x^(2*k) / (1 - x^(5*k+2)) ) / ( Sum_{k in Z} x^k / (1 - x^(5*k+1)) ). - Seiichi Manyama, Jul 29 2024

Extensions

More terms from Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), Jun 20 2000

A340455 G.f.: Sum_{n>=0} x^(2*n)/(1 - x^(5*n+2)) - x*Sum_{n>=0} x^(3*n)/(1 - x^(5*n+3)).

Original entry on oeis.org

1, -1, 2, 0, 0, 0, 2, -2, 2, 1, 0, 0, 1, -2, 2, 0, 2, 0, 2, -2, 0, 0, 0, 2, 2, -2, 2, 0, -1, 0, 4, -2, 2, -1, 0, 0, 0, 0, 2, 0, 2, 0, 2, -2, 2, 0, -2, 0, 2, -2, 2, 2, 0, 0, 2, -2, 2, 1, 2, -2, 0, -2, 2, 0, 1, 2, 2, -2, 0, 0, 0, 0, 2, -2, 4
Offset: 0

Views

Author

Paul D. Hanna, Jan 20 2021

Keywords

Comments

The g.f. of this sequence equals the numerator of George E. Andrews' expression for the cube of Ramanujan's continued fraction. See references given in A007325.

Examples

			G.f.: P(q) = 1 - q + 2*q^2 + 2*q^6 - 2*q^7 + 2*q^8 + q^9 + q^12 - 2*q^13 + 2*q^14 + 2*q^16 + 2*q^18 - 2*q^19 + 2*q^23 + 2*q^24 - 2*q^25 + 2*q^26 - q^28 + ...
Given the g.f. of this sequence,
P(q) = Sum_{n>=0} q^(2*n)/(1 - q^(5*n+2)) - q*Sum_{n>=0} q^(3*n)/(1 - q^(5*n+3))
and the g.f. of A340456,
Q(q) = Sum_{n>=0} q^n/(1 - q^(5*n+1)) - q^3*Sum_{n>=0} q^(4*n)/(1 - q^(5*n+4))
then
R(q)^3 = P(q)/Q(q) where
Q(q) = 1 + 2*q + 2*q^2 + q^3 + 2*q^4 + 2*q^5 + 2*q^6 + q^7 + 2*q^8 + 2*q^9 + 2*q^10 + 2*q^12 + 4*q^13 + 2*q^14 + q^16 + ...
R(q)^3 = 1 - 3*q + 6*q^2 - 7*q^3 + 3*q^4 + 6*q^5 - 17*q^6 + 24*q^7 - 21*q^8 + 6*q^9 + 21*q^10 - 54*q^11 + 77*q^12 - 72*q^13 + 24*q^14 + 64*q^15 + ...;
here, R(q) is the expansion of Ramanujan's continued fraction (A007325).
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A = prod(m=0,n\5+1, (1-x^(5*m+5) +x*O(x^n))^2 * (1-x^(5*m+1))*(1-x^(5*m+4)) / ( (1-x^(5*m+2))^2*(1-x^(5*m+3))^2 +x*O(x^n) ) ));polcoeff(A,n)}
    for(n=0,100,print1(a(n),", "))
    
  • PARI
    {S(j,k,n) = sum(m=0,n, x^(j*m)/(1 - x^(5*m+k) +x*O(x^n)) ) }
    {a(n) = polcoeff( S(2,2,n) - x*S(3,3,n), n)}
    for(n=0,100,print1(a(n),", "))

Formula

G.f.: Product_{n>=0} (1 - x^(n+1)) * (1 - x^(5*n+5)) / ( (1 - x^(5*n+2))^3 * (1 - x^(5*n+3))^3 ).
G.f.: Product_{n>=0} (1 - x^(5*n+5))^2 * (1 - x^(5*n+1))*(1 - x^(5*n+4)) / ( (1 - x^(5*n+2))^2*(1 - x^(5*n+3))^2 ).
G.f.: [ Sum_{n>=0} x^n/(1 - x^(5*n+3)) - x * Sum_{n>=0} x^(4*n)/(1 - x^(5*n+2)) ] * R(x), where R(q) is the expansion of Ramanujan's continued fraction (A007325).

A285443 Expansion of Product_{k>0} ((1-x^{5k-2}) * (1-x^{5k-3})/((1-x^{5k-1}) * (1-x^{5k-4})))^3 in powers of x.

Original entry on oeis.org

1, 3, 3, -2, -6, 0, 12, 9, -15, -28, 3, 48, 33, -48, -87, 7, 135, 90, -134, -234, 21, 356, 237, -330, -575, 42, 831, 540, -762, -1296, 107, 1848, 1191, -1633, -2769, 210, 3842, 2448, -3366, -5634, 444, 7722, 4889, -6624, -11028, 840, 14871, 9342, -12636, -20877
Offset: 0

Views

Author

Seiichi Manyama, Apr 19 2017

Keywords

Crossrefs

Prod_{k>0} ((1-x^{5k-1}) * (1-x^{5k-4})/((1-x^{5k-2}) * (1-x^{5k-3})))^m: A285444 (m=-4), this sequence (m=-3), A285442 (m=-2), A003823 (m=-1), A007325 (m=1), A055101 (m=2), A055102 (m=3), A055103 (m=4).

Formula

a(0) = 1, a(n) = (3/n)*Sum_{k=1..n} A109091(k)*a(n-k) for n > 0.
Expansion of cube of continued fraction 1 + x/(1 + x^2/(1 + x^3/(1 + x^4/(1 + ...)))). - Ilya Gutkovskiy, Apr 19 2017
G.f.: ( Sum_{k in Z} x^k / (1 - x^(5*k+1)) ) / ( Sum_{k in Z} x^(2*k) / (1 - x^(5*k+2)) ). - Seiichi Manyama, Jul 29 2024

A340453 G.f.: Product_{n>=0} (1 - x^(5*n+5))^2 / ( (1 - x^(5*n+1))*(1 - x^(5*n+4)) ).

Original entry on oeis.org

1, 1, 1, 1, 2, 0, 1, 1, 2, 1, 1, 0, 2, 1, 0, 2, 2, 0, 1, 1, 2, 1, 1, -1, 2, 1, 2, 1, 2, 1, 0, 1, 1, 1, 1, 0, 2, 2, 1, 1, 2, -1, 1, 2, 2, 1, 0, 0, 3, 0, 1, 1, 2, 0, 1, 1, 2, 2, 1, 0, 2, 1, 0, 1, 2, 0, 1, 1, 0, 1, 2, 2, 2, 1, 2, 0, 2, -1, 0, 1, 2
Offset: 0

Views

Author

Paul D. Hanna, Jan 16 2021

Keywords

Examples

			G.f.: P(q) = 1 + q + q^2 + q^3 + 2*q^4 + q^6 + q^7 + 2*q^8 + q^9 + q^10 + 2*q^12 + q^13 + 2*q^15 + 2*q^16 + q^18 + q^19 + 2*q^20 + ...
Given the g.f. of this sequence,
P(q) = Product_{n>=0} (1 - q^(5*n+5))^2 / ( (1 - q^(5*n+1))*(1 - q^(5*n+4)) ),
and the g.f. of A340454,
Q(q) = Product_{n>=0} (1 - q^(5*n+5))^2 / ( (1 - q^(5*n+2))*(1 - q^(5*n+3)) ),
then R(q) = P(q)/Q(q) where
Q(q) = 1 + q^2 + q^3 + q^4 - q^5 + 2*q^6 + q^8 + q^9 + q^10 + q^12 - q^13 + q^14 + 2*q^15 + q^16 + 2*q^18 - q^19 + q^20 + ...
and
R(q) = 1 + q - q^3 + q^5 + q^6 - q^7 - 2*q^8 + 2*q^10 + 2*q^11 - q^12 - 3*q^13 - q^14 + 3*q^15 + 3*q^16 - 2*q^17 - 5*q^18 - q^19 + 6*q^20 + ...;
here, R(q) is the expansion of Ramanujan's continued fraction (A007325).
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A = prod(m=0,n, (1 - x^(5*m+5))^2 / ( (1 - x^(5*m+1))*(1 - x^(5*m+4)) +x*O(x^n)) )); polcoeff(A,n)}
    for(n=0,80,print1(a(n),", "))
    
  • PARI
    {a(n) = my(A = sum(m=0,n, x^(1*m)/(1 - x^(5*m+2) +x*O(x^n)) ) - x^2 * sum(m=0,n, x^(3*m)/(1 - x^(5*m+4) +x*O(x^n)) )); polcoeff(A,n)}
    for(n=0,80,print1(a(n),", "))
    
  • PARI
    {a(n) = my(A = sum(m=0,n, x^(2*m)/(1 - x^(5*m+1) +x*O(x^n)) ) - x^2 * sum(m=0,n, x^(4*m)/(1 - x^(5*m+3) +x*O(x^n)) )); polcoeff(A,n)}
    for(n=0,80,print1(a(n),", "))

Formula

G.f.: Sum_{n>=0} x^(1*n)/(1 - x^(5*n+2)) - x^2 * Sum_{n>=0} x^(3*n)/(1 - x^(5*n+4)).
G.f.: Sum_{n>=0} x^(2*n)/(1 - x^(5*n+1)) - x^2 * Sum_{n>=0} x^(4*n)/(1 - x^(5*n+3)).
G.f.: Sum_{n>=0} x^(1*n)/(1 - x^(5*n+2)) - x^2 * Sum_{n>=0} x^(4*n)/(1 - x^(5*n+3)).
G.f.: Sum_{n>=0} x^(2*n)/(1 - x^(5*n+1)) - x^2 * Sum_{n>=0} x^(3*n)/(1 - x^(5*n+4)).
G.f.: [ Sum_{n>=0} x^n/(1 - x^(5*n+1)) - x^3 * Sum_{n>=0} x^(4*n)/(1 - x^(5*n+4)) ] * R(x), where R(q) is the expansion of Ramanujan's continued fraction (A007325).

A285442 Expansion of Product_{k>0} ((1-x^{5k-2}) * (1-x^{5k-3})/((1-x^{5k-1}) * (1-x^{5k-4})))^2 in powers of x.

Original entry on oeis.org

1, 2, 1, -2, -2, 2, 5, 0, -8, -6, 7, 14, 1, -18, -15, 14, 30, 2, -40, -32, 32, 66, 6, -82, -65, 60, 125, 8, -157, -120, 117, 238, 19, -286, -222, 206, 419, 28, -507, -386, 366, 732, 55, -864, -659, 610, 1224, 86, -1442, -1090, 1016, 2024, 147, -2350, -1775, 1632
Offset: 0

Views

Author

Seiichi Manyama, Apr 19 2017

Keywords

Crossrefs

Product_{k>0} ((1-x^{5k-1}) * (1-x^{5k-4})/((1-x^{5k-2}) * (1-x^{5k-3})))^m: A285444 (m=-4), A285443 (m=-3), this sequence (m=-2), A003823 (m=-1), A007325 (m=1), A055101 (m=2), A055102 (m=3), A055103 (m=4).

Programs

  • Mathematica
    nmax = 60; CoefficientList[Series[Product[((1-x^(5k-2)) * (1-x^(5k-3)) / ((1-x^(5k-1)) * (1-x^(5k-4))))^2, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Oct 13 2017 *)

Formula

a(0) = 1, a(n) = (2/n)*Sum_{k=1..n} A109091(k)*a(n-k) for n > 0.
Expansion of square of continued fraction 1 + x/(1 + x^2/(1 + x^3/(1 + x^4/(1 + ...)))). - Ilya Gutkovskiy, Apr 19 2017
From Seiichi Manyama, Jul 29 2024: (Start)
G.f.: ( Sum_{k in Z} x^k / (1 - x^(5*k+1)) ) / ( Sum_{k in Z} x^(3*k) / (1 - x^(5*k+1)) ).
G.f.: ( Sum_{k in Z} x^k / (1 - x^(5*k+2)) ) / ( Sum_{k in Z} x^(2*k) / (1 - x^(5*k+2)) ). (End)

A340454 G.f.: Product_{n>=0} (1 - x^(5*n+5))^2 / ( (1 - x^(5*n+2))*(1 - x^(5*n+3)) ).

Original entry on oeis.org

1, 0, 1, 1, 1, -1, 2, 0, 1, 1, 1, 0, 1, -1, 1, 2, 1, 0, 2, -1, 1, 0, 1, 0, 2, 0, 0, 2, 2, -1, 1, 0, 1, 0, 1, 0, 2, -1, 1, 2, 0, 1, 2, 0, 1, 0, 1, -2, 1, 0, 2, 2, 1, -1, 2, 0, 1, 1, 1, 0, 2, -2, 1, 2, 0, 0, 1, 1, 0, 0, 1, 0, 3, 1, 1, 0, 1, -1, 2, 0, 2
Offset: 0

Views

Author

Paul D. Hanna, Jan 16 2021

Keywords

Examples

			G.f.: Q(q) = 1 + q^2 + q^3 + q^4 - q^5 + 2*q^6 + q^8 + q^9 + q^10 + q^12 - q^13 + q^14 + 2*q^15 + q^16 + 2*q^18 - q^19 + q^20 + ...
Given the g.f. of this sequence,
Q(q) = Product_{n>=0} (1 - q^(5*n+5))^2 / ( (1 - q^(5*n+2))*(1 - q^(5*n+3)) ),
and the g.f. of A340453,
P(q) = Product_{n>=0} (1 - q^(5*n+5))^2 / ( (1 - q^(5*n+1))*(1 - q^(5*n+4)) ),
then R(q) = P(q)/Q(q) where
P(q) = 1 + q + q^2 + q^3 + 2*q^4 + q^6 + q^7 + 2*q^8 + q^9 + q^10 + 2*q^12 + q^13 + 2*q^15 + 2*q^16 + q^18 + q^19 + 2*q^20 + ...
and
R(q) = 1 + q - q^3 + q^5 + q^6 - q^7 - 2*q^8 + 2*q^10 + 2*q^11 - q^12 - 3*q^13 - q^14 + 3*q^15 + 3*q^16 - 2*q^17 - 5*q^18 - q^19 + 6*q^20 + ...;
here, R(q) is the expansion of Ramanujan's continued fraction (A007325).
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A = prod(m=0,n, (1 - x^(5*m+5))^2 / ( (1 - x^(5*m+2))*(1 - x^(5*m+3)) +x*O(x^n) ) )); polcoeff(A,n)}
    for(n=0,80,print1(a(n),", "))
    
  • PARI
    {a(n) = my(A = sum(m=0,n, x^(1*m)/(1 - x^(5*m+3) +x*O(x^n)) ) - x * sum(m=0,n, x^(2*m)/(1 - x^(5*m+4) +x*O(x^n)) )); polcoeff(A,n)}
    for(n=0,80,print1(a(n),", "))
    
  • PARI
    {a(n) = my(A = sum(m=0,n, x^(3*m)/(1 - x^(5*m+1) +x*O(x^n)) ) - x * sum(m=0,n, x^(4*m)/(1 - x^(5*m+2) +x*O(x^n)) )); polcoeff(A,n)}
    for(n=0,80,print1(a(n),", "))

Formula

G.f.: Sum_{n>=0} x^(1*n)/(1 - x^(5*n+3)) - x * Sum_{n>=0} x^(2*n)/(1 - x^(5*n+4)).
G.f.: Sum_{n>=0} x^(3*n)/(1 - x^(5*n+1)) - x * Sum_{n>=0} x^(4*n)/(1 - x^(5*n+2)).
G.f.: Sum_{n>=0} x^(1*n)/(1 - x^(5*n+3)) - x * Sum_{n>=0} x^(4*n)/(1 - x^(5*n+2)).
G.f.: Sum_{n>=0} x^(3*n)/(1 - x^(5*n+1)) - x * Sum_{n>=0} x^(2*n)/(1 - x^(5*n+4)).
G.f.: [ Sum_{n>=0} x^(2*n)/(1 - x^(5*n+2)) - x * Sum_{n>=0} x^(3*n)/(1 - x^(5*n+3)) ] / R(x), where R(q) is the expansion of Ramanujan's continued fraction (A007325).

A374900 Expansion of Sum_{k in Z} x^k / (1 - x^(7*k+1)).

Original entry on oeis.org

1, 2, 2, 2, 2, 1, 2, 2, 2, 3, 2, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 1, 4, 2, 2, 2, 0, 2, 2, 3, 4, 2, 0, 2, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 0, 2, 2, 0, 2, 2, 2, 3, 2, 0, 2, 2, 4, 0, 2, 2, 2, 2, 2, 3, 2, 0, 2, 4, 2, 2, 0, 0, 2, 2, 2, 4, 2, 0, 2, 2, 2, 2, 2, 0, 2, 4, 4, 2, 2, 0, 2, 2, 2, 2, 2
Offset: 0

Views

Author

Seiichi Manyama, Jul 31 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=110, x='x+O('x^N)); Vec(sum(k=-N, N, x^k/(1-x^(7*k+1))))
    
  • PARI
    my(N=110, x='x+O('x^N)); Vec(prod(k=1, N, (1-x^(7*k))^2*(1-x^(7*k-2))*(1-x^(7*k-5))/((1-x^(7*k-1))*(1-x^(7*k-6)))^2))

Formula

G.f.: Product_{k>0} (1-x^(7*k))^2 * (1-x^(7*k-2)) * (1-x^(7*k-5)) / ((1-x^(7*k-1)) * (1-x^(7*k-6)))^2.

A375062 Expansion of 1 / Sum_{k in Z} x^k / (1 - x^(5*k+1)).

Original entry on oeis.org

1, -2, 2, -1, -2, 6, -9, 9, -4, -7, 22, -34, 33, -13, -25, 71, -103, 97, -39, -69, 196, -282, 263, -102, -182, 499, -703, 645, -248, -433, 1181, -1650, 1499, -568, -988, 2652, -3660, 3294, -1240, -2129, 5681, -7790, 6960, -2595, -4438, 11732, -15959, 14161, -5252
Offset: 0

Views

Author

Seiichi Manyama, Jul 29 2024

Keywords

Crossrefs

Convolution inverse of A340456.

Programs

  • PARI
    my(N=50, x='x+O('x^N)); Vec(1/sum(k=-N, N, x^k/(1-x^(5*k+1))))
    
  • PARI
    my(N=50, x='x+O('x^N)); Vec(prod(k=1, N, ((1-x^(5*k-1))*(1-x^(5*k-4)))^3/((1-x^k)*(1-x^(5*k)))))

Formula

G.f.: Product_{k>0} ((1-x^(5*k-1)) * (1-x^(5*k-4)))^3 / ((1-x^k) * (1-x^(5*k))).
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