A220353
G.f.: Sum_{n>=0} (1 - (1-x)^n)^n.
Original entry on oeis.org
1, 1, 4, 23, 176, 1697, 19805, 271669, 4285195, 76430799, 1521161530, 33422603485, 803584699252, 20986514811397, 591616582807036, 17905570068475471, 579092313210791549, 19931241131544637637, 727395001560116046739, 28057672464546863483509, 1140566596105346550309751, 48735378037084078566334897, 2183719157723179429519093520, 102386962560815561519635957007
Offset: 0
G.f.: A(x) = 1 + x + 4*x^2 + 23*x^3 + 176*x^4 + 1697*x^5 + 19805*x^6 +...
where the g.f. satisfies the identities:
(1) A(x) = 1 + x + (2*x - x^2)^2 + (3*x - 3*x^2 + x^3)^3 + (4*x - 6*x^2 + 4*x^3 - x^4)^4 + (5*x - 10*x^2 + 10*x^3 - 5*x^4 + x^5)^5 +...
(2) A(x) = (1-x) + (1-x)^2*(2*x - x^2) + (1-x)^3*(3*x - 3*x^2 + x^3)^2 + (1-x)^4*(4*x - 6*x^2 + 4*x^3 - x^4)^3 + (1-x)^5*(5*x - 10*x^2 + 10*x^3 - 5*x^4 + x^5)^4 +...
-
terms = 24;
gf = 1 + Sum[(1 - (1 - x)^n)^n, {n, 1, terms}] + O[x]^terms;
CoefficientList[gf, x] (* Jean-François Alcover, Jul 01 2018 *)
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{a(n)=local(q=1/(1-x+x*O(x^n)),A=1);A=sum(k=0,n,q^(-k^2)*(q^k-1)^k);polcoeff(A,n)}
for(n=0,30,print1(a(n),", "))
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{a(n)=local(q=1/(1-x+x*O(x^n)),A=1);A=sum(k=1,n+1,q^(-k^2)*(q^k-1)^(k-1));polcoeff(A,n)}
for(n=0,30,print1(a(n),", "))
A301584
G.f.: Sum_{n>=0} ((1+x)^(2*n) - 1)^n.
Original entry on oeis.org
1, 2, 17, 264, 5784, 163610, 5667551, 232280480, 10991951114, 589780778314, 35379149504709, 2346218124687516, 170439977706143335, 13459938431949414118, 1148107512505151099653, 105194122765096703619248, 10303686044959088279454117, 1074408525677705370497704526, 118828297870115694372235974855, 13893778686151373846512389392672, 1712370237144948501135060958863978
Offset: 0
G.f.: A(x) = 1 + 2*x + 17*x^2 + 264*x^3 + 5784*x^4 + 163610*x^5 + 5667551*x^6 + 232280480*x^7 + 10991951114*x^8 + 589780778314*x^9 + ...
such that
A(x) = 1 + ((1+x)^2-1) + ((1+x)^4-1)^2 + ((1+x)^6-1)^3 + ((1+x)^8-1)^4 + ((1+x)^10-1)^5 + ((1+x)^12-1)^6 + ((1+x)^14-1)^7 + ...
Also,
A(x) = 1/2 + (1+x)^2/(1 + (1+x)^2)^2 + (1+x)^8/(1 + (1+x)^4)^3 + (1+x)^18/(1 + (1+x)^6)^4 + (1+x)^32/(1 + (1+x)^8)^5 + (1+x)^50/(1 + (1+x)^10)^6 + ...
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{a(n) = my(A,o=x*O(x^n)); A = sum(m=0,n, ((1+x +o)^(2*m) - 1)^m ); polcoeff(A,n)}
for(n=0,30,print1(a(n),", "))
A302615
G.f.: Sum_{n>=0} (3 + (1+x)^n)^n / (4 + (1+x)^n)^(n+1).
Original entry on oeis.org
1, 1, 10, 130, 2390, 56714, 1644138, 56327820, 2226708772, 99761490536, 4995375316146, 276464859358474, 16757956600528786, 1104116777798713154, 78565751676021256606, 6004629888868350015506, 490572645247461234631946, 42665124626946741636482996, 3935474733572880332326074450, 383756013888633346483785849474
Offset: 0
G.f.: A(x) = 1 + x + 10*x^2 + 130*x^3 + 2390*x^4 + 56714*x^5 + 1644138*x^6 + 56327820*x^7 + 2226708772*x^8 + 99761490536*x^9 + ...
such that
A(x) = 1/5 + (3 + (1+x))/(4 + (1+x))^2 + (3 + (1+x)^2)^2/(4 + (1+x)^2)^3 + (3 + (1+x)^3)^3/(4 + (1+x)^3)^4 + (3 + (1+x)^4)^4/(4 + (1+x)^4)^5 + (3 + (1+x)^5)^5/(4 + (1+x)^5)^6 + (3 + (1+x)^6)^6/(4 + (1+x)^6)^7 + ...
Also,
A(x) = 1 + ((1+x) - 1)/(4 - 3*(1+x))^2 + ((1+x)^2 - 1)^2/(4 - 3*(1+x)^2)^3 + ((1+x)^3 - 1)^3/(4 - 3*(1+x)^3)^4 + ((1+x)^4 - 1)^4/(4 - 3*(1+x)^4)^5 + ((1+x)^5 - 1)^5/(4 - 3*(1+x)^5)^6 + ((1+x)^6 - 1)^6/(4 - 3*(1+x)^6)^7 + ...
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{a(n) = my(A=1, o=x*O(x^n)); A = sum(m=0, n, ((1+x +o)^m - 1)^m / (4 - 3*(1+x +o)^m)^(m+1)); polcoeff(A, n)}
for(n=0, 30, print1(a(n), ", "))
A122419
Number of labeled digraphs with n arcs and with no vertex of indegree 0.
Original entry on oeis.org
1, 0, 1, 8, 93, 1354, 23900, 496244, 11855700, 320428318, 9667220397, 322072882348, 11744421711587, 465270864839688, 19899234175413257, 913836170567749048, 44849438199960187278, 2342666125012348876152
Offset: 0
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A122418 := proc(n) option remember ; add( combinat[stirling2](n,k)*(k-1)^n*k!,k=0..n) ; end: A122419 := proc(n) option remember ; add( combinat[stirling1](n,k)*A122418(k),k=0..n)/n! ; end: for n from 0 to 30 do printf("%d, ",A122419(n)) ; od ; # R. J. Mathar, May 18 2007
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nmax=20; CoefficientList[Series[Sum[((1+x)^(n-1)-1)^n, {n, 0, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, May 06 2014 *)
A301585
G.f.: Sum_{n>=0} ((1+x)^(3*n) - 1)^n.
Original entry on oeis.org
1, 3, 39, 910, 29949, 1271751, 66116065, 4066082856, 288701376912, 23240635243591, 2091554595246705, 208085119389952134, 22676957610808295192, 2686515300821612112411, 343760257348413122290260, 47248346582443326267328400, 6942339982115290619799947901, 1085919469129099832397573088863, 180160797497273341662653292624309, 31598815412054398239059538582525618
Offset: 0
G.f.: A(x) = 1 + 3*x + 39*x^2 + 910*x^3 + 29949*x^4 + 1271751*x^5 + 66116065*x^6 + 4066082856*x^7 + 288701376912*x^8 + ...
such that
A(x) = 1 + ((1+x)^3-1) + ((1+x)^6-1)^2 + ((1+x)^9-1)^3 + ((1+x)^12-1)^4 + ((1+x)^15-1)^5 + ((1+x)^18-1)^6 + ((1+x)^21-1)^7 + ...
Also,
A(x) = 1/2 + (1+x)^3/(1 + (1+x)^3)^2 + (1+x)^12/(1 + (1+x)^6)^3 + (1+x)^27/(1 + (1+x)^9)^4 + (1+x)^48/(1 + (1+x)^12)^5 + (1+x)^75/(1 + (1+x)^15)^6 + ...
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{a(n) = my(A,o=x*O(x^n)); A = sum(m=0,n, ((1+x +o)^(3*m) - 1)^m ); polcoeff(A,n)}
for(n=0,30,print1(a(n),", "))
A301586
G.f.: Sum_{n>=0} ((1+x)^(4*n) - 1)^n.
Original entry on oeis.org
1, 4, 70, 2180, 95729, 5422192, 375951144, 30833206304, 2919367902648, 313380517364324, 37606931999739230, 4988933437333555060, 724960700435104219679, 114519163835687116024256, 19538926882901715534673728, 3580844611314789257667535968, 701546780854024941112271649610, 146318317830136401429653726419700, 32367591848747955557013839920695374, 7569528177000020896435962191564396740
Offset: 0
G.f.: A(x) = 1 + 4*x + 70*x^2 + 2180*x^3 + 95729*x^4 + 5422192*x^5 + 375951144*x^6 + 30833206304*x^7 + ...
such that
A(x) = 1 + ((1+x)^4-1) + ((1+x)^8-1)^2 + ((1+x)^12-1)^3 + ((1+x)^16-1)^4 + ((1+x)^20-1)^5 + ((1+x)^24-1)^6 + ((1+x)^28-1)^7 + ...
Also,
A(x) = 1/2 + (1+x)^4/(1 + (1+x)^4)^2 + (1+x)^16/(1 + (1+x)^8)^3 + (1+x)^36/(1 + (1+x)^12)^4 + (1+x)^64/(1 + (1+x)^16)^5 + (1+x)^100/(1 + (1+x)^20)^6 + ...
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{a(n) = my(A,o=x*O(x^n)); A = sum(m=0,n, ((1+x +o)^(4*m) - 1)^m ); polcoeff(A,n)}
for(n=0,30,print1(a(n),", "))
A302614
G.f.: Sum_{n>=0} (2 + (1+x)^n)^n / (3 + (1+x)^n)^(n+1).
Original entry on oeis.org
1, 1, 8, 91, 1474, 30765, 785053, 23682833, 824522797, 32537599175, 1435199414014, 69973425937141, 3736662443907962, 216901789032691605, 13598124265965160130, 915670842666691879191, 65913110467411283181409, 5050836914009172555862713, 410501468976427335127369669, 35269929119728622895198302033, 3194195105084750546987502710855
Offset: 0
G.f.: A(x) = 1 + x + 8*x^2 + 91*x^3 + 1474*x^4 + 30765*x^5 + 785053*x^6 + 23682833*x^7 + 824522797*x^8 + 32537599175*x^9 + ...
such that
A(x) = 1/4 + (2 + (1+x))/(3 + (1+x))^2 + (2 + (1+x)^2)^2/(3 + (1+x)^2)^3 + (2 + (1+x)^3)^3/(3 + (1+x)^3)^4 + (2 + (1+x)^4)^4/(3 + (1+x)^4)^5 + (2 + (1+x)^5)^5/(3 + (1+x)^5)^6 + (2 + (1+x)^6)^6/(3 + (1+x)^6)^7 + ...
Also,
A(x) = 1 + ((1+x) - 1)/(3 - 2*(1+x))^2 + ((1+x)^2 - 1)^2/(3 - 2*(1+x)^2)^3 + ((1+x)^3 - 1)^3/(3 - 2*(1+x)^3)^4 + ((1+x)^4 - 1)^4/(3 - 2*(1+x)^4)^5 + ((1+x)^5 - 1)^5/(3 - 2*(1+x)^5)^6 + ((1+x)^6 - 1)^6/(3 - 2*(1+x)^6)^7 + ...
RELATED INFINITE SERIES.
(1) At x = -1/3: the following sums are equal
S1 = Sum_{n>=0} 3^n * (2*3^n + 2^n)^n / (3^(n+1) + 2^n)^(n+1),
S1 = Sum_{n>=0} (-3)^n * (3^n - 2^n)^n / (3^(n+1) - 2^(n+1))^(n+1).
Explicitly,
S1 = 1/4 + 3*8/11^2 + 9*22^2/31^3 + 27*62^3/89^4 + 81*178^4/259^5 + 243*518^5/761^6 + 729*1522^6/2251^7 + 2187*4502^7/6689^8 + 6561*13378^8/19939^9 + 19683*39878^9/59561^10 + ...
S1 = 1 - 3*1/5^2 + 9*5^2/19^3 - 27*19^3/65^4 + 81*65^4/211^5 - 243*211^5/665^6 + 729*665^6/2059^7 - 2187*2059^7/6305^8 + 6561*6305^8/19171^9 - 19683*19171^9/58025^10 + ...
where S1 = 0.90501051059439877583104471171480036033530856741889530664913...
(2) At x = -1/2: the following sums are equal
S2 = Sum_{n>=0} 2^n * (2^(n+1) + 1)^n / (3*2^n + 1)^(n+1),
S2 = Sum_{n>=0} (-2)^n * (2^n - 1)^n / (3*2^n - 2)^(n+1).
Explicitly,
S2 = 1/4 + 2*5/7^2 + 4*9^2/13^3 + 8*17^3/25^4 + 16*33^4/49^5 + 32*65^5/97^6 + 64*129^6/193^7 + 128*257^7/385^8 + 256*513^8/769^9 + 512*1025^9/1537^10 + ...
S2 = 1 - 2*1/4^2 + 4*3^2/10^3 - 8*7^3/22^4 + 16*15^4/46^5 - 32*31^5/94^6 + 64*63^6/190^7 - 128*127^7/382^8 + 256*255^8/766^9 - 512*511^9/1534^10 + ...
where S2 = 0.90222608896798122564942421232120719521782835530371831680447...
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{a(n) = my(A=1, o=x*O(x^n)); A = sum(m=0, n, ((1+x +o)^m - 1)^m / (3 - 2*(1+x +o)^m)^(m+1)); polcoeff(A, n)}
for(n=0, 30, print1(a(n), ", "))
A227619
G.f.: A(x) = 1+x + Sum_{n>=2} (A(x)^n - 1)^n.
Original entry on oeis.org
1, 1, 4, 63, 1278, 29764, 758065, 20611793, 590579518, 17707907024, 553879330720, 18066513887790, 615744470668778, 22014659625607877, 830262409494773896, 33243718957578687811, 1422095813097928147636, 65311403344808947050730, 3227884786251446164710376
Offset: 0
G.f.: A(x) = 1 + x + 4*x^2 + 63*x^3 + 1278*x^4 + 29764*x^5 +...
where
A(x) = 1+x + (A(x)^2 - 1)^2 + (A(x)^3 - 1)^3 + (A(x)^4 - 1)^4 + (A(x)^5 - 1)^5 +...
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{a(n)=local(A=1+x);for(i=1,n,A=1+x+sum(k=2,n,(A^k-1 +x*O(x^n))^k));polcoeff(A,n)}
for(n=0,20,print1(a(n),", "))
A232192
G.f. satisfies: A(x) = 1 + x*Sum_{n>=0} (A(x)^n - 1)^n.
Original entry on oeis.org
1, 1, 1, 5, 44, 519, 7590, 132347, 2689046, 62644234, 1651650774, 48731341965, 1592908456996, 57173688136781, 2235773294509565, 94608603077007214, 4306708055122614542, 209823573154587335730, 10892496561736261641371, 600171728539156939466278
Offset: 0
G.f.: A(x) = 1 + x + x^2 + 5*x^3 + 44*x^4 + 519*x^5 + 7590*x^6 + 132347*x^7 + 2689046*x^8 + 62644234*x^9 + 1651650774*x^10 +...
where
A(x) = 1 + x + x*(A(x)-1) + x*(A(x)^2-1)^2 + x*(A(x)^3-1)^3 + x*(A(x)^4-1)^4 + x*(A(x)^5-1)^5 + x*(A(x)^6-1)^6 + x*(A(x)^7-1)^7 +...
Also,
A(x) = 1 + x/2 + x*A(x)/(1 + A(x))^2 + x*A(x)^4/(1 + A(x)^2)^3 + x*A(x)^9/(1 + A(x)^3)^4 + x*A(x)^16/(1 + A(x)^4)^5 + x*A(x)^25/(1 + A(x)^5)^6 + ...
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{a(n)=local(A=1+x); for(i=1, n, A=1+x*sum(m=0, n, (A^m-1+x*O(x^n))^m)); polcoeff(A, n)}
for(n=0,20,print1(a(n),", "))
A317798
G.f.: Sum_{n>=0} (3*(1+x)^n - 1)^n / 3^(n+1).
Original entry on oeis.org
1, 15, 786, 69261, 8554530, 1359020643, 263929299177, 60582032629791, 16046282916588207, 4817035600778756553, 1616224504900354928832, 599373591433178971787007, 243449152911402772344286998, 107482020677618238226506065235, 51249638236281451846248205583562, 26247197050200652206165329786055981, 14369481728948627418149559363836673273
Offset: 0
G.f.: A(x) = 1 + 15*x + 786*x^2 + 69261*x^3 + 8554530*x^4 + 1359020643*x^5 + 263929299177*x^6 + 60582032629791*x^7 + 16046282916588207*x^8 + ...
such that
A(x) = 1/3 + (3*(1+x) - 1)/3^2 + (3*(1+x)^2 - 1)^3/3^3 + (3*(1+x)^3 - 1)^3/3^4 + (3*(1+x)^4 - 1)^4/3^5 + (3*(1+x)^5 - 1)^5/3^6 + ...
Also,
A(x) = 1/4 + 3*(1+x)/(3 + (1+x))^2 + 3^2*(1+x)^4/(3 + (1+x)^2)^3 + 3^3*(1+x)^9/(3 + (1+x)^3)^4 + 3^4*(1+x)^16/(3 + (1+x)^4)^5 + 3^5*(1+x)^25/(3 + (1+x)^5)^6 + 3^6*(1+x)^36/(3 + (1+x)^6)^7 + ...
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