A260491
Coefficients in asymptotic expansion of sequence A077607.
Original entry on oeis.org
1, -4, 0, -8, -76, -752, -8460, -107520, -1522124, -23717424, -402941324, -7407988448, -146479479308, -3099229422352, -69863683041868, -1671667534710720, -42318672085310540, -1130167625049525232, -31758424368739424780, -936840101208573355680
Offset: 0
A077607(n) / (-n!) ~ 1 - 4/n - 8/n^3 - 76/n^4 - 752/n^5 - 8460/n^6 - ...
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nmax = 30; b = CoefficientList[Assuming[Element[x, Reals], Series[x^4*E^(2/x)/(ExpIntegralEi[1/x] - x*E^(1/x))^2, {x, 0, nmax}]], x]; Flatten[{1, Table[Sum[b[[k+1]]*StirlingS2[n-1, k-1], {k, 1, n}], {n, 1, nmax}]}] (* Vaclav Kotesovec, Aug 03 2015 *)
A078140
Convolutory inverse of signed lower Wythoff sequence.
Original entry on oeis.org
1, 3, 5, 9, 17, 30, 52, 90, 154, 262, 446, 758, 1285, 2176, 3683, 6230, 10533, 17803, 30085, 50831, 85873, 145063, 245037, 413891, 699082, 1180761, 1994293, 3368302, 5688920, 9608292, 16227841, 27407792, 46289925, 78180465, 132041227
Offset: 1
a(5) = 17 = -[w(5)*a(1)-w(4)*a(2)+w(3)*a(3)-w(2)*a(4)] = -8*1+6*3-4*5+3*9. (a(1),a(2),...,a(n))(*)(w(1),-w(2),w(3),...,-d*w(n)) = (1,0,0,...,0), where (*) denotes convolution, w = lower Wythoff sequence, A000201.
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CoefficientList[Series[1/Sum[Floor[GoldenRatio*(k + 1)] (-x)^k, {k, 0, 50}],
{x, 0,50}], x] (* Clark Kimberling, Dec 12 2016 *)
Original entry on oeis.org
1, 1, 4, 22, 148, 1156, 10192, 99688, 1069168, 12468208, 157071424, 2126386912, 30797423680, 475378906432, 7793485765888, 135284756985472, 2479535560687360, 47860569736036096, 970606394944476160, 20635652201785613824, 459015456156148876288, 10662527360021306782720
Offset: 0
(1/2)*log(1 + 2*x + 6*x^2 + ... + ((n+1)!/1!)*x^n + ...)
= x + (4/2)*x^2 + (22/3)*x^3 + (148/4)*x^4 + (1156/5)*x^5 + ...
- Robert Israel, Table of n, a(n) for n = 0..410
- Paul Barry, A note on number triangles that are almost their own production matrix, arXiv:1804.06801 [math.CO], 2018.
- Richard J. Martin and Michael J. Kearney, Integral representation of certain combinatorial recurrences, Combinatorica: 35:3 (2015), 309-315.
- A. N. Stokes, Continued fraction solutions of the Riccati equation, Bull. Austral. Math. Soc. Vol. 25 (1982), 207-214.
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N:= 30: # to get a(0) to a(N)
g:= 1/2*log(add((n+1)!*x^n,n=0..N+1)):
S:= series(g,x,N+1);
1, seq(j*coeff(S,x,j),j=0..N); # Robert Israel, Jul 10 2015
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T[n_, k_] := T[n, k] = Which[n<0 || k<0, 0, k==0 || k==1, 1, n==0, k!, True, (T[n-1, k+1]-T[n-1, k])/n - Sum[T[n, j] T[n-1, k-j], {j, 1, k-1}]];
a[n_] := T[2, n];
Table[a[n], {n, 0, 21}] (* Jean-François Alcover, Aug 09 2018 *)
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{a(n)=if(n<0,0,if(n==0,1, (n/2)*polcoeff(log(sum(m=0,n,(m+1)!/1!*x^m)),n)))}
A225127
Convolutory inverse of the nonprimes.
Original entry on oeis.org
1, -4, 10, -24, 59, -146, 360, -886, 2182, -5376, 13244, -32624, 80364, -197968, 487672, -1201319, 2959297, -7289859, 17957662, -44236464, 108971015, -268436517, 661259918, -1628931424, 4012669610, -9884711639, 24349755585, -59982589144, 147759635098
Offset: 1
(1,4,6,8,9,...)**(1,-4,10,-24,59,...) = (1,0,0,0,0,...), where ** denotes convolution.
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z = 1000; c = Complement[Range[z], Prime[Range[PrimePi[z]]]]; r[n_] := r[n] = c[[n]]; k[n_] := k[n] = 0; k[1] = 1; a[n_] := a[n] = (k[n] - Sum[r[i]*a[n - i + 1], {i, 2, n}])/r[1]; t = Table[a[n], {n, 1, 40}] (* A225127 *)
A296617
Expansion of 1/Sum_{k>=0} (k+1)^(k+1)*x^k.
Original entry on oeis.org
1, -4, -11, -104, -1388, -22980, -446524, -9882944, -244592124, -6684031040, -199824449532, -6488250797312, -227456440349948, -8565880619584896, -345018776767586572, -14805421633750610240, -674514253891722861612, -32522567276377571337728
Offset: 0
A303671
a(n) = [x^n] (6 / Sum_{k=0..n} (k+3)!*x^k)^(1/2).
Original entry on oeis.org
1, -2, -4, -20, -140, -1192, -11656, -127072, -1517480, -19624400, -272656064, -4046157472, -63844717184, -1067307017600, -18846094327360, -350578477836160, -6854465726916640, -140564170444594880, -3017526392523529600, -67690323794750627200
Offset: 0
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[seq(coeff(series((factorial(3)/add(factorial(k+3)*x^k,k=0..n))^(1/2), x,30),x,n),n=0..25)]; # Muniru A Asiru, Apr 29 2018
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N=66; x='x+O('x^N); Vec((3!/sum(k=0, N, (k+3)!*x^k))^(1/2))
A303672
a(n) = [x^n] (5040 / Sum_{k=0..n} (k+7)!*x^k)^(1/4).
Original entry on oeis.org
1, -2, -8, -60, -600, -7152, -96456, -1430544, -22933920, -393013280, -7144207808, -137001926144, -2760226854816, -58242464679360, -1283886660610560, -29506641823939200, -705788634473952000, -17544801385483584000, -452659831142363014400
Offset: 0
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[seq(coeff(series((factorial(7)/add(factorial(k+7)*x^k,k=0..n))^(1/4), x,30),x,n),n=0..25)]; # Muniru A Asiru, Apr 29 2018
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N=66; x='x+O('x^N); Vec((7!/sum(k=0, N, (k+7)!*x^k))^(1/4))
A303673
a(n) = [x^n] (15! / Sum_{k=0..n} (k+15)!*x^k)^(1/8).
Original entry on oeis.org
1, -2, -16, -204, -3264, -60384, -1239912, -27591408, -655324704, -16443029408, -432731364992, -11882079044992, -339084517212576, -10026995732141760, -306530743192692480, -9669854410016300160, -314315622535266332160
Offset: 0
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[seq(coeff(series((factorial(15)/add(factorial(k+15)*x^k,k=0..n))^(1/8), x,30),x,n),n=0..25)]; # Muniru A Asiru, Apr 29 2018
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N=66; x='x+O('x^N); Vec((15!/sum(k=0, N, (k+15)!*x^k))^(1/8))
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