This site is supported by donations to The OEIS Foundation.

 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!)
 A229452 G.f.: exp( Sum_{n>=1} (3*n)!/(3!*n!^3) * x^n/n ). 2
 1, 1, 8, 101, 1569, 27445, 518407, 10333243, 214320244, 4583132411, 100411556533, 2243625355010, 50955869372055, 1173262656151429, 27332509319090516, 643208905017756216, 15270427859720369204, 365356267775348553277, 8801688936499808334602 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Self-convolution 6th power yields A229451. LINKS EXAMPLE G.f.: A(x) = 1 + 6*x + 63*x^2 + 866*x^3 + 13899*x^4 + 246366*x^5 +... where log(A(x)) = x + 15*x^2/2 + 280*x^3/3 + 5775*x^4/4 + 126126*x^5/5 + 2858856*x^6/6 +...+ A060542(n)*x^n/n +... PROG (PARI) {a(n)=polcoeff(exp(sum(k=1, n, (3*k)!/(3!*k!^3)*x^k/k) +x*O(x^n)), n)} for(n=0, 25, print1(a(n), ", ")) CROSSREFS Cf. A229451, A060542, A006480 (De Bruijn's S(3,n)). Sequence in context: A317598 A238947 A291536 * A199816 A302870 A317862 Adjacent sequences:  A229449 A229450 A229451 * A229453 A229454 A229455 KEYWORD nonn AUTHOR Paul D. Hanna, Sep 23 2013 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.

Last modified December 15 20:00 EST 2019. Contains 330000 sequences. (Running on oeis4.)