login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A063023 Reversion of y - y^2 - y^4 - y^5. 3
0, 1, 1, 2, 6, 21, 77, 292, 1143, 4592, 18821, 78364, 330512, 1409149, 6063526, 26298592, 114849110, 504595293, 2228824203, 9891723114, 44087704836, 197255893945, 885630834120, 3988872011820, 18017892014655 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Robert Israel, Table of n, a(n) for n = 0..1471

Vladimir Kruchinin, The method for obtaining expressions for coefficients of reverse generating functions, arXiv:1211.3244 [math.CO], 2012.

Index entries for reversions of series

FORMULA

a(n) = sum(k=0..n-1, (sum(j=floor((n-k-1)/3)..floor((n-k-1)/2), binomial(j,n-k-2*j-1)*binomial(k,j)))*binomial(n+k-1,n-1))/n, n>0, a(0)=0. - Vladimir Kruchinin, May 26 2011

MAPLE

with(gfun):

F:= RootOf(y-y^2-y^4-y^5-x, y):

DE:=holexprtodiffeq(F, g(x)):

Rec:= diffeqtorec(DE, g(x), a(n)):

f:= rectoproc(Rec, a(n), remember):

map(f, [$0..50]); # Robert Israel, Jan 08 2019

MATHEMATICA

CoefficientList[InverseSeries[Series[y - y^2 - y^4 - y^5, {y, 0, 30}], x], x]

PROG

(Maxima)

a(n):=sum((sum(binomial(j, n-k-2*j-1)*binomial(k, j), j, floor((n-k-1)/3), floor((n-k-1)/2)))*binomial(n+k-1, n-1), k, 0, n-1)/n; /* Vladimir Kruchinin, May 26 2011 */

(Sage) # Function Reversion defined in A063022.

Reversion(x - x^2 - x^4 - x^5, 25) # Peter Luschny, Jan 08 2019

(PARI) concat(0, Vec(serreverse(x - x^2 - x^4 - x^5 + O(x^30)))) \\ Michel Marcus, Jan 08 2019

CROSSREFS

Cf. A063019, A063022.

Sequence in context: A242622 A279561 A294048 * A150188 A150189 A144169

Adjacent sequences:  A063020 A063021 A063022 * A063024 A063025 A063026

KEYWORD

nonn,easy

AUTHOR

Olivier Gérard, Jul 05 2001

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 11 02:18 EST 2019. Contains 329910 sequences. (Running on oeis4.)