Original entry on oeis.org
1, 9, 91, 1063, 14193, 213953, 3602891, 67168527, 1375636129, 30741614905, 745133551611, 19485223248311, 547092691302545, 16422216867929457, 524970306508659691, 17809453107819266335, 639153386976421052481, 24196474723945543441769, 963736849031626750711451, 40289411871795861783689799
Offset: 1
-
A286781_ser(N, t='t) = {
my(x='x+O('x^N), y0=1+O('x^N), y1=0, n=1);
while(n++,
y1 = (1 + x*y0 + 2*x^2*y0')*(1 - x*y0*(1-t))/(1-x*y0)^2;
if (y1 == y0, break()); y0 = y1;);
y0;
};
Kol(K,N=20) = {
my(s = A286781_ser(N+K, 't+O('t^(K+1))));
vector(N, n, polcoeff(polcoeff(s, K+n-1), K));
};
Kol(1)
Original entry on oeis.org
1, 23, 416, 7344, 134613, 2620379, 54636792, 1223392968, 29409134545, 757686550455, 20870680635528, 612964613117960, 19140704352872949, 633710701752022635, 22185391759982205904, 819180275431111135536, 31826528430233802890049, 1298154677953792936043447, 55473817874169725876166480
Offset: 2
-
A286781_ser(N, t='t) = {
my(x='x+O('x^N), y0=1+O('x^N), y1=0, n=1);
while(n++,
y1 = (1 + x*y0 + 2*x^2*y0')*(1 - x*y0*(1-t))/(1-x*y0)^2;
if (y1 == y0, break()); y0 = y1;);
y0;
};
Kol(K,N=20) = {
my(s = A286781_ser(N+K, 't+O('t^(K+1))));
vector(N, n, polcoeff(polcoeff(s, K+n-1), K));
};
Kol(2)
Original entry on oeis.org
1, 46, 1350, 34362, 842751, 20862684, 533394516, 14251251012, 400275122533, 11849888387786, 370032953752618, 12183464636804638, 422529226131247475, 15413172354966378040, 590459747844232859976, 23715530712277152761928, 997006212536288359365609, 43800374567467950834916070
Offset: 3
Original entry on oeis.org
1, 80, 3550, 125195, 4009832, 124266346, 3854188670, 121943460540, 3979525634005, 134806148044750, 4756728585598416, 175132764223880035, 6731931366383154760, 270129431174068396380, 11308903054417009540644, 493544598057755406560688, 22431785171561428611320865
Offset: 4
Original entry on oeis.org
1, 127, 8085, 382358, 15653598, 598415692, 22280470762, 828351390146, 31225895068199, 1204894853397543, 47870402081423775, 1965205314867907972, 83531844407610101388, 3679988322044604002256, 168093873703636990132596, 7960504783782783371445468
Offset: 5
Original entry on oeis.org
1, 189, 16576, 1023340, 52563182, 2445890678, 108248782988, 4693939818672, 203214066766123, 8891156436472127, 396276632116578640, 18084968846773765272, 847923332620865268252, 40927316768759272656876, 2036183873275911481501656, 104482592642320957223810448
Offset: 6
Original entry on oeis.org
1, 268, 31356, 2471008, 156688950, 8769288752, 457164358716, 22959079494036, 1135195898868631, 56066461542293032, 2793059847097230456, 141275485011659499936, 7287917154352619470284, 384587934464798917826784, 20802129691800205763744280, 1154767942465769017202459544
Offset: 7
Original entry on oeis.org
1, 366, 55650, 5493004, 423998498, 28236562692, 1719625254528, 99364697625603, 5581585635090040, 309848573192308938, 17191725056094651066, 960908576231662848594, 54403314773991195041214, 3132006013784614723699158, 183841318769012678798846646, 11022935912713058281592718756
Offset: 8
Original entry on oeis.org
1, 3, 20, 189, 2232, 31130, 497016, 8907885, 176829104, 3849436062, 91187523000, 2335691914050, 64344487654800, 1897619527612692, 59667237154623280, 1993022006345620605, 70488571028815935072, 2631925423768158446390, 103469607286411235941944, 4272438866376100717458486
Offset: 0
A(x) = 1 + 3*x + 20*x^2 + 189*x^3 + 2232*x^4 + 31130*x^5 + ...
- Gheorghe Coserea, Table of n, a(n) for n = 0..301
- Michael Borinsky, Renormalized asymptotic enumeration of Feynman diagrams, arXiv:1703.00840 [hep-th], 2017.
- E. Z. Kuchinskii and M. V. Sadovskii, Combinatorics of Feynman diagrams for the problems with gaussian random field, arXiv:cond-mat/9706062 [cond-mat.dis-nn], 1997.
- Luca G. Molinari, Hedin's equations and enumeration of Feynman's diagrams, arXiv:cond-mat/0401500 [cond-mat.str-el], 2005.
-
max = 22; (* B(x) is A000699(x) *) B[_] = 0;
Do[B[x_] = x + x^2 D[B[x]^2/x, x] + O[x]^max // Normal, max];
A[x_] = (1 - x/B[x])/x + O[x]^max;
Drop[CoefficientList[A[x], x], -2] (* Jean-François Alcover, Oct 25 2018 *)
-
A286781_ser(N, t='t) = {
my(x='x+O('x^N), y0=1+O('x^N), y1=0, n=1);
while(n++,
y1 = (1 + x*y0 + 2*x^2*y0')*(1 - x*y0*(1-t))/(1-x*y0)^2;
if (y1 == y0, break()); y0 = y1;);
y0;
};
Vec(A286781_ser(20,1))
-
A000699_seq(N) = {
my(a = vector(N)); a[1] = 1;
for (n=2, N, a[n] = sum(k=1, n-1, (2*k-1)*a[k]*a[n-k])); a;
};
A286794_seq(N) = Vec((1-1/Ser(A000699_seq(N+1)))/x);
A286794_seq(20)
A286782
Triangle T(n,k) read by rows: coefficients of polynomials P_n(t) defined in Formula section.
Original entry on oeis.org
1, 1, 6, 3, 50, 45, 5, 518, 637, 161, 7, 6354, 9567, 3744, 414, 9, 89782, 156123, 80784, 14850, 880, 11, 1435330, 2781389, 1749969, 446706, 46150, 1651, 13, 25625910, 54043365, 39305685, 12641265, 1877925, 121275, 2835, 15, 505785122, 1141864959, 928825464, 354665628, 68167144, 6500086, 281792, 4556, 17, 10944711398, 26137086451, 23244466392, 10134495804, 2361060574, 297418362, 19443460, 595764, 6954, 19
Offset: 0
A(x;t) = 1 + x + (6 + 3*t)*x^2 + (50 + 45*t + 5*t^2)*x^3 + ...
Triangle starts:
n\k [0] [1] [2] [3] [4] [5] [6] [7]
[0] 1;
[1] 1;
[2] 6, 3;
[3] 50, 45, 5;
[4] 518, 637, 161, 7;
[5] 6354, 9567, 3744, 414, 9;
[6] 89782, 156123, 80784, 14850, 880, 11;
[7] 1435330, 2781389, 1749969, 446706, 46150, 1651, 13;
[8] 25625910, 54043365, 39305685, 12641265, 1877925, 121275, 2835, 15;
[9] ...
-
max = 10; y0[x_, t_] = 1; y1[x_, t_] = 0; For[n = 1, n <= max, n++, y1[x_, t_] = (1 + x*y0[x, t] + 2*x^2*D[y0[x, t], x])*(1 - x*y0[x, t]*(1 - t))/(1 - x*y0[x, t])^2 + O[x]^n // Normal; y0[x_, t_] = y1[x, t]];
row[n_] := (2n+1) CoefficientList[Coefficient[y0[x, t], x, n], t];
T[0, 0] = 1; T[n_, k_] := row[n-1][[k+1]];
Table[T[n, k], {n, 0, max}, {k, 0, If[n == 0, 0, n-1]}] // Flatten (* Jean-François Alcover, May 19 2017, adapted from PARI *)
-
A286781_ser(N,t='t) = {
my(x='x+O('x^N), y0=1+O('x^N), y1=0, n=1);
while(n++,
y1 = (1 + x*y0 + 2*x^2*y0')*(1 - x*y0*(1-t))/(1-x*y0)^2;
if (y1 == y0, break()); y0 = y1;);
y0;
};
A286782_ser(N,t='t) = my(s=A286781_ser(N,t)); 1 + x*s + 2*x^2 * deriv(s,'x);
concat(apply(p->Vecrev(p), Vec(A286782_ser(10))))
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