A248871
Coefficients in asymptotic expansion of sequence A107895.
Original entry on oeis.org
1, 1, 3, 12, 66, 450, 3679, 35260, 388511, 4844584, 67502450, 1039929756, 17556193609, 322321551868, 6393505020803, 136245752898586, 3103879644045050, 75268872986970840, 1935571325829192247, 52605265683008056660, 1506530437404419817467
Offset: 0
A107895(n) / n! ~ 1 + 1/n + 3/n^2 + 12/n^3 + 66/n^4 + 450/n^5 + 3679/n^6 + ...
A179327
G.f.: Product_{n>=1} 1/(1-x^n)^((n-1)!).
Original entry on oeis.org
1, 1, 2, 4, 11, 37, 167, 925, 6164, 47630, 418227, 4105887, 44529413, 528398441, 6807143686, 94588353184, 1409913624333, 22437692156739, 379673925360239, 6806484898946045, 128862141334488784, 2569079946351669286, 53797816061915662161, 1180533553597621952193
Offset: 0
G.f.: A(x) = 1 + x + 2*x^2 + 4*x^3 + 11*x^4 + 37*x^5 + 167*x^6 +...
A(x) = 1/((1-x)*(1-x^2)*(1-x^3)^2*(1-x^4)^6*(1-x^5)^24*(1-x^6)^120*...).
log(A(x)) = x + 3*x^2/2 + 7*x^3/3 + 27*x^4/4 + 121*x^5/5 + 729*x^6/6 + 5041*x^7/7 + 40347*x^8/8 +...+ A062363(n)*x^n/n +...
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b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
add(b(n-i*j, i-1)*binomial((i-1)!+j-1, j), j=0..n/i)))
end:
a:= n-> b(n$2):
seq(a(n), n=0..23); # Alois P. Heinz, Aug 10 2021
-
nmax=20; CoefficientList[Series[Product[1/(1-x^k)^((k-1)!),{k,1,nmax}],{x,0,nmax}],x] (* Vaclav Kotesovec, Mar 14 2015 *)
-
{a(n)=polcoeff(exp(sum(m=1,n,sumdiv(m,d,d!)*x^m/m)+x*O(x^n)),n)}
A261052
Expansion of Product_{k>=1} (1+x^k)^(k!).
Original entry on oeis.org
1, 1, 2, 8, 31, 157, 915, 6213, 48240, 423398, 4147775, 44882107, 531564195, 6837784087, 94909482330, 1413561537884, 22482554909451, 380269771734265, 6815003300096013, 128992737080703803, 2571218642722865352, 53835084737513866662, 1181222084520177393143
Offset: 0
-
b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
add(binomial(i!, j)*b(n-i*j,i-1), j=0..n/i)))
end:
a:= n-> b(n$2):
seq(a(n), n=0..25); # Alois P. Heinz, Aug 08 2015
-
nmax=25; CoefficientList[Series[Product[(1+x^k)^(k!),{k,1,nmax}],{x,0,nmax}],x]
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seq(n)={Vec(exp(x*Ser(dirmul(vector(n, n, n!), -vector(n, n, (-1)^n/n)))))} \\ Andrew Howroyd, Jun 22 2018
A107894
Sum over the products of factorials of parts in all partitions of n where the sum runs over the number of different parts only.
Original entry on oeis.org
1, 1, 3, 9, 35, 167, 943, 6379, 48945, 429651, 4189865, 45307601, 535518109, 6883110373, 95435065935, 1420468921893, 22577620176887, 381695573051099, 6837601709298811, 129375694813679215, 2578070946813526485, 53964818587883937807, 1183805926540690127573
Offset: 0
The partitions of 5 are 1+1+1+1+1, 1+1+1+2, 1+1+3, 1+2+2, 1+4, 2+3, 5, the corresponding products of factorials of parts are (when multiple parts are counted once only) 1!, 1!*2!, 1!*3!, 1!*2!, 1!*4!, 2!*3!, 5! and their sum is a(5) = 167.
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b:= proc(n, i) option remember;
`if`(n=0 or i<2, 1, b(n, i-1) +i!*add(b(n-i*j, i-1), j=1..n/i))
end:
a:= n-> b(n, n):
seq(a(n), n=0..30); # Alois P. Heinz, Apr 04 2012
-
Total[Times@@@(Union/@IntegerPartitions[#]!)]&/@Range[20] (* Harvey P. Dale, Feb 26 2011 *)
b[n_, i_] := b[n, i] = If[n==0 || i<2, 1, b[n, i-1] + i!*Sum[b[n-i*j, i-1], {j, 1, n/i}]]; a[n_] := b[n, n]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Oct 29 2015, after Alois P. Heinz *)
A261047
Euler transform of (n+1)!.
Original entry on oeis.org
1, 2, 9, 40, 212, 1248, 8400, 63576, 540858, 5132564, 53952742, 623324184, 7855144818, 107224120980, 1575511525794, 24784246515256, 415435624535225, 7389692971336602, 138992875726543381, 2755750468146310688, 57433108983590606292
Offset: 0
-
a:= proc(n) option remember; `if`(n=0, 1, add(add(d*
(d+1)!, d=numtheory[divisors](j))*a(n-j), j=1..n)/n)
end:
seq(a(n), n=0..30); # Alois P. Heinz, Jul 28 2017
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nmax=20; CoefficientList[Series[Product[1/(1-x^k)^((k+1)!), {k, 1, nmax}], {x, 0, nmax}], x]
A305867
Expansion of Product_{k>=1} 1/(1 - x^k)^(2*k-1)!!.
Original entry on oeis.org
1, 1, 4, 19, 130, 1120, 11960, 151595, 2230550, 37361755, 701873371, 14610774346, 333746628499, 8298025724194, 223049950124065, 6444634486214748, 199165237980655863, 6555102341516877027, 228905611339161301812, 8452656930719845696590, 329075775511339959533232, 13471099892869946627980017
Offset: 0
-
N:= 25:
S:=series(mul((1-x^k)^(-doublefactorial(2*k-1)),k=1..N),x,N+1):
seq(coeff(S,x,n),n=0..N); # Robert Israel, Jun 12 2018
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nmax = 21; CoefficientList[Series[Product[1/(1 - x^k)^(2 k - 1)!!, {k, 1, nmax}], {x, 0, nmax}], x]
a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d (2 d - 1)!!, {d, Divisors[k]}] a[n - k], {k, 1, n}]/n]; Table[a[n], {n, 0, 21}]
A280088
Expansion of Product_{k>=1} 1/(1 - x^k)^(k!!).
Original entry on oeis.org
1, 1, 3, 6, 17, 38, 112, 280, 882, 2416, 8253, 24458, 91051, 289704, 1172288, 3980034, 17413820, 62706119, 294608079, 1118820630, 5603910081, 22328924231, 118432939871, 492897768426, 2752203529333, 11918139966134, 69709167028426, 313080284080648, 1910245872252972, 8873669214476627, 56283324138424814, 269790676411694902
Offset: 0
- Vincenzo Librandi, Table of n, a(n) for n = 0..300
- M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to arXiv version]
- M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to Lin. Alg. Applic. version together with omitted figures]
- N. J. A. Sloane, Transforms
- Index entries for sequences related to factorial numbers
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nmax = 31; CoefficientList[Series[Product[1/(1 - x^k)^(k!!), {k, 1, nmax}], {x, 0, nmax}], x]
A321875
a(n) = Sum_{d|n} d*d!.
Original entry on oeis.org
1, 5, 19, 101, 601, 4343, 35281, 322661, 3265939, 36288605, 439084801, 5748023639, 80951270401, 1220496112085, 19615115520619, 334764638530661, 6046686277632001, 115242726706374263, 2311256907767808001, 48658040163569088701, 1072909785605898275299
Offset: 1
-
m:=25; R:=PowerSeriesRing(Integers(), m); Coefficients(R!( (&+[k*Factorial(k)*x^k/(1 - x^k): k in [1..(m+2)]]) )); // G. C. Greubel, Nov 20 2018
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Table[Sum[d d!, {d, Divisors[n]}], {n, 21}]
nmax = 21; Rest[CoefficientList[Series[Sum[k k! x^k/(1 - x^k), {k, 1, nmax}], {x, 0, nmax}], x]]
nmax = 21; Rest[CoefficientList[Series[-Log[Product[(1 - x^k)^k!, {k, 1, nmax}]], {x, 0, nmax}], x] Range[0, nmax]]
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a(n) = sumdiv(n, d, d*d!); \\ Michel Marcus, Nov 20 2018
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s = sum(k*factorial(k)*x^k/(1-x^k) for k in (1..24));
(s/x).series(x, 21).coefficients(x, sparse=false) # Peter Luschny, Nov 21 2018
A380497
Euler transform of primorial numbers.
Original entry on oeis.org
1, 2, 9, 46, 314, 3072, 37641, 603510, 11148030, 249327430, 7040987792, 216220333314, 7895699690498, 321315600822232, 13770543972819903, 644232544408157820, 33954066516677635554, 1994206929690480710244, 121461036181617491970561, 8111955386813996410196454, 574814471423312085719652432
Offset: 0
- Eric Weisstein's World of Mathematics, Primorial.
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p:= proc(n) option remember; `if`(n<1, 1, p(n-1)*ithprime(n)) end:
a:= proc(n) option remember; `if`(n=0, 1, add(a(n-j)*
add(d*p(d), d=numtheory[divisors](j)), j=1..n)/n)
end:
seq(a(n), n=0..20); # Alois P. Heinz, Jan 25 2025
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nmax = 20; CoefficientList[Series[Product[1/(1 - x^k)^Product[Prime[j], {j, k}], {k, 1, nmax}], {x, 0, nmax}], x]
primorial[n_] := Product[Prime[j], {j, 1, n}]; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d primorial[d], {d, Divisors[j]}] a[n - j], {j, 1, n}]/n]; Table[a[n], {n, 0, 20}]
Original entry on oeis.org
1, 4, 18, 114, 900, 8845, 103861, 1427122, 22486706, 399906140, 7922936720, 173013117604, 4127746294408, 106806183646594, 2978731438384738, 89065499057526433, 2842061902985159593, 96395720127638538076, 3462922846509648162418
Offset: 0
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Rest[CoefficientList[Series[Product[1/(1 - x^k)^((k-1)!*(2^k-1)), {k, 1, 20}], {x, 0, 20}], x]] (* Vaclav Kotesovec, Aug 07 2015 *)
Showing 1-10 of 11 results.
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