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 1-3 of 3 results.

A299427 Square table where T(n,k) = binomial(n*(n+k), k) * n/(n+k), for n>=1, k>=0, as read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 4, 1, 1, 9, 14, 1, 1, 16, 63, 48, 1, 1, 25, 184, 408, 165, 1, 1, 36, 425, 1872, 2565, 572, 1, 1, 49, 846, 6175, 17980, 15939, 2002, 1, 1, 64, 1519, 16536, 82775, 167552, 98670, 7072, 1, 1, 81, 2528, 38318, 292581, 1059380, 1535352, 610740, 25194, 1, 1, 100, 3969, 79808, 861175, 4874688, 13177125, 13934752, 3786588, 90440, 1
Offset: 0

Views

Author

Paul D. Hanna, Feb 19 2018

Keywords

Examples

			This table begins:
n=1: [1,  1,    1,      1,       1,         1,          1, ...];
n=2: [1,  4,   14,     48,     165,       572,       2002, ...];
n=3: [1,  9,   63,    408,    2565,     15939,      98670, ...];
n=4: [1, 16,  184,   1872,   17980,    167552,    1535352, ...];
n=5: [1, 25,  425,   6175,   82775,   1059380,   13177125, ...];
n=6: [1, 36,  846,  16536,  292581,   4874688,   78119454, ...];
n=7: [1, 49, 1519,  38318,  861175,  18008676,  358919022, ...];
n=8: [1, 64, 2528,  79808, 2214640,  56592320, 1367090208, ...];
n=9: [1, 81, 3969, 153117, 5132565, 157000275, 4507103601, ...];
...
Row generating functions R(x,n)^(n^2) begin:
R(x,1) = 1 + x + x^2 + x^3 + x^4 + x^5 + x^6 + ...
R(x,2)^4 = 1 + 4*x + 14*x^2 + 48*x^3 + 165*x^4 + 572*x^5  + ...
R(x,3)^9 = 1 + 9*x + 63*x^2 + 408*x^3 + 2565*x^4 + 15939*x^5 + ...
R(x,4)^16 = 1 + 16*x + 184*x^2 + 1872*x^3 + 17980*x^4 + 167552*x^5 + ...
R(x,5)^25 = 1 + 25*x + 425*x^2 + 6175*x^3 + 82775*x^4 + 1059380*x^5 + ...
R(x,6)^36 = 1 + 36*x + 846*x^2 + 16536*x^3 + 292581*x^4 + 4874688*x^5 + ...
...
Related series R(x,n) = 1 + x*R(x,n)^n begin:
R(x,1) = 1 + x + x^2 + x^3 + x^4 + x^5 + ...
R(x,2) = 1 + x + 2*x^2 + 5*x^3 + 14*x^4 + 42*x^5 + ...
R(x,3) = 1 + x + 3*x^2 + 12*x^3 + 55*x^4 + 273*x^5 + ...
R(x,4) = 1 + x + 4*x^2 + 22*x^3 + 140*x^4 + 969*x^5 + ...
R(x,5) = 1 + x + 5*x^2 + 35*x^3 + 285*x^4 + 2530*x^5 + ...
R(x,6) = 1 + x + 6*x^2 + 51*x^3 + 506*x^4 + 5481*x^5 + ...
...
where R(x,n)^m = Sum_{k>=0} C(m + n*k, k) * m/(m + n*k) * x^k.
...
		

Crossrefs

Cf. A299044 (antidiagonal sums), A299428 (diagonal), A299429.

Programs

  • PARI
    {T(n,k) = binomial(n*(n+k), k) * n/(n+k) }
    /* Print as a square table of first 9 rows */
    for(n=1,9,print1("n="n": [",); for(k=0,8,print1(T(n,k),", ")); print1("...];");print(""))
    /* Print as a Flattened table read by antidiagonals */
    for(n=1,10,for(k=0,n,print1(T(n-k+1,k),", ")))

Formula

G.f. for row n: R(x,n)^(n^2) = Sum_{k>=0} C(n*(n+k), k) * n/(n+k) * x^k, where R(x,n) = 1 + x*R(x,n)^n.

A299043 G.f. Sum_{n>=0} Series_Reversion( x*(1-x)^n )^n.

Original entry on oeis.org

1, 1, 2, 7, 33, 191, 1293, 9941, 85137, 801067, 8194281, 90367696, 1067146336, 13418399528, 178808377777, 2514944176091, 37204969293137, 577131827509491, 9362170099804501, 158438822236836110, 2791230865213193695, 51090157185364462103, 969892719975254406849, 19066076629590290124814, 387539455534509836620517, 8134022943287699194376826, 176073319016203896275830713
Offset: 0

Views

Author

Paul D. Hanna, Feb 18 2018

Keywords

Examples

			G.f. A(x) = 1 + x + 2*x^2 + 7*x^3 + 33*x^4 + 191*x^5 + 1293*x^6 + 9941*x^7 + 85137*x^8 + 801067*x^9 + 8194281*x^10 + ...
such that
A(x) = 1 + x*R(x,2) + x^2*R(x,3)^4 + x^3*R(x,4)^9 + x^4*R(x,5)^16 + x^5*R(x,6)^25 + x^6*R(x,7)^36 + ...
where series R(x,n) = 1 + x*R(x,n)^n begin:
R(x,1) = 1 + x + x^2 + x^3 + x^4 + x^5 + ...
R(x,2) = 1 + x + 2*x^2 + 5*x^3 + 14*x^4 + 42*x^5 + ...
R(x,3) = 1 + x + 3*x^2 + 12*x^3 + 55*x^4 + 273*x^5 + ...
R(x,4) = 1 + x + 4*x^2 + 22*x^3 + 140*x^4 + 969*x^5 + ...
R(x,5) = 1 + x + 5*x^2 + 35*x^3 + 285*x^4 + 2530*x^5 + ...
R(x,6) = 1 + x + 6*x^2 + 51*x^3 + 506*x^4 + 5481*x^5 + ...
...
and series R(x,n+1)^(n^2) begin:
R(x,2) = 1 + x + 2*x^2 + 5*x^3 + 14*x^4 + 42*x^5 + 132*x^6 + ...
R(x,3)^4 = 1 + 4*x + 18*x^2 + 88*x^3 + 455*x^4 + 2448*x^5 + ...
R(x,4)^9 = 1 + 9*x + 72*x^2 + 570*x^3 + 4554*x^4 + 36855*x^5 + ...
R(x,5)^16 = 1 + 16*x + 200*x^2 + 2320*x^3 + 26180*x^4 + 292448*x^5 + ...
R(x,6)^25 = 1 + 25*x + 450*x^2 + 7175*x^3 + 108100*x^4 + 1581255*x^5 + ...
R(x,7)^36 = 1 + 36*x + 882*x^2 + 18480*x^3 + 357399*x^4 + 6601644*x^5 + ...
...
		

Crossrefs

Cf. A299044.

Programs

  • PARI
    {a(n) = my(A); A = sum(m=0,n+1, serreverse( x*(1-x)^m +x^2*O(x^n) )^m ); polcoeff(A,n)}
    for(n=0,30,print1(a(n),", "))
    
  • PARI
    {a(n) = if(n==0,1, sum(k=0,n, binomial(n*(n-k) + k,k) * (n-k)^2/(n*(n-k) + k) ) )}
    for(n=0,30,print1(a(n),", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n satisfies the following expressions.
(1) A(x) = Sum_{n>=0} Series_Reversion( x*(1-x)^n )^n.
(2) A(x) = Sum_{n>=1} x^n * R(x,n+1)^(n^2), where
(2.a) R(x,n+1) = 1 + x*R(x,n+1)^(n+1),
(2.b) R(x,n+1)^n = Series_Reversion( x*(1-x)^n ) / x,
(2.c) R(x,n+1)^n = Sum_{k>=0} C(n*(k+1) + k, k) * n/(n*(k+1) + k) * x^k,
(2.d) R(x,n+1)^(n^2) = Sum_{k>=0} C(n*(n+k) + k, k) * n^2/(n*(n+k) + k) * x^k.
FORMULAS FOR TERMS.
a(n) = Sum_{k=0..n} binomial(n*(n-k) + k, k) * (n-k)^2/(n*(n-k) + k).

A299426 E.g.f. Sum_{n>=0} Series_Reversion( x*exp(-n*x) )^n.

Original entry on oeis.org

1, 1, 4, 39, 688, 18765, 722016, 37003267, 2426725120, 197569640889, 19498786969600, 2288864397602871, 314642887620065280, 50002239358837749061, 9086161251793519280128, 1870292375864728408312875, 432549223770637009573052416, 111598253780454986901562293489, 31918043775392401233962828169216, 10063176613379061071841096012386911, 3479934178969181147698311417364480000
Offset: 0

Views

Author

Paul D. Hanna, Feb 18 2018

Keywords

Examples

			E.g.f. A(x) = 1 + x + 4*x^2/2! + 39*x^3/3! + 688*x^4/4! + 18765*x^5/5! + 722016*x^6/6! + 37003267*x^7/7! + 2426725120*x^8/8! + ...
such that
A(x) = 1 + x*W(x,1) + x^2*W(x,2)^4 + x^3*W(x,3)^9 + x^4*W(x,4)^16 + x^5*W(x,5)^25 + x^6*W(x,6)^36 + ...
where series W(x,n) = exp( x*W(x,n)^n ) begin:
W(x,1) = 1 + x + 3*x^2/2! + 16*x^3/3! + 125*x^4/4! + 1296*x^5/5! + ...
W(x,2) = 1 + x + 5*x^2/2! + 49*x^3/3! + 729*x^4/4! + 14641*x^5/5! + ...
W(x,3) = 1 + x + 7*x^2/2! + 100*x^3/3! + 2197*x^4/4! + 65536*x^5/5! + ...
W(x,4) = 1 + x + 9*x^2/2! + 169*x^3/3! + 4913*x^4/4! + 194481*x^5/5! + ...
W(x,5) = 1 + x + 11*x^2/2! + 256*x^3/3! + 9261*x^4/4! + 456976*x^5/5! + ...
W(x,6) = 1 + x + 13*x^2/2! + 361*x^3/3! + 15625*x^4/4! + 923521*x^5/5! + ...
...
and series W(x,n)^n = Series_Reversion( x*exp(-n*x) ) / x begin:
W(x,1) = 1 + x + 3*x^2/2! + 16*x^3/3! + 125*x^4/4! + 1296*x^5/5! + ...
W(x,2)^2 = 1 + 2*x + 12*x^2/2! + 128*x^3/3! + 2000*x^4/4! + ...
W(x,3)^3 = 1 + 3*x + 27*x^2/2! + 432*x^3/3! + 10125*x^4/4! + ...
W(x,4)^4 = 1 + 4*x + 48*x^2/2! + 1024*x^3/3! + 32000*x^4/4! + ...
W(x,5)^5 = 1 + 5*x + 75*x^2/2! + 2000*x^3/3! + 78125*x^4/4! + ...
W(x,6)^6 = 1 + 6*x + 108*x^2/2! + 3456*x^3/3! + 162000*x^4/4! + ...
...
and series W(x,n)^(n^2) begin:
W(x,1) = 1 + x + 3*x^2/2! + 16*x^3/3! + 125*x^4/4! + 1296*x^5/5! + ...
W(x,2)^4 = 1 + 4*x + 32*x^2/2! + 400*x^3/3! + 6912*x^4/4! + ...
W(x,3)^9 = 1 + 9*x + 135*x^2/2! + 2916*x^3/3! + 83349*x^4/4! + ...
W(x,4)^16 = 1 + 16*x + 384*x^2/2! + 12544*x^3/3! + 524288*x^4/4! + ...
W(x,5)^25 = 1 + 25*x + 875*x^2/2! + 40000*x^3/3! + 2278125*x^4/4! + ...
W(x,6)^36 = 1 + 36*x + 1728*x^2/2! + 104976*x^3/3! + 7776000*x^4/4! + ...
...
		

Crossrefs

Programs

  • PARI
    {a(n) = my(A); A = sum(m=0,n+1, serreverse( x*exp(-m*x +x^2*O(x^n) ) )^m ); n!*polcoeff(A,n)}
    for(n=0,20,print1(a(n),", "))
    
  • PARI
    {a(n) = if(n==0,1, sum(k=0,n, n!/k! * n^(k-1) * (n-k)^(k+1) ) )}
    for(n=0,20,print1(a(n),", "))

Formula

E.g.f. A(x) = Sum_{n>=0} a(n)*x^n/n! satisfies the following expressions.
(1) A(x) = Sum_{n>=0} Series_Reversion( x*exp(-n*x) )^n.
(2) A(x) = Sum_{n>=1} x^n * W(x,n)^(n^2), where
(2.a) W(x,n) = exp( -LambertW(-n*x)/n ),
(2.b) W(x,n) = exp( x*W(x,n)^n ),
(2.c) W(x,n)^n = Series_Reversion( x*exp(-n*x) ) / x,
(2.d) W(x,n)^n = Sum_{k>=0} n^k * (k+1)^(k-1) * x^k/k!;
(2.e) W(x,n)^(n^2) = Sum_{k>=0} n^(k+1) * (n+k)^(k-1) * x^k/k!.
FORMULAS FOR TERMS.
a(n) = Sum_{k=0..n} n!/k! * n^(k-1) * (n-k)^(k+1).
Showing 1-3 of 3 results.