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 A092958 a(1) = 1, a(2) = (1+2)*(2+3), a(3) = (1+2+3)*(2+3+4)*(3+4+5), ... etc. Or a(n) = (T(n))*(T(n)+n)*(T(n)+2n)*(T(n)+3n)*... n terms. where T(n) = n(n+1)/2 given by A000217. 1
 1, 15, 648, 55440, 7875000, 1674728055, 498078806400, 197378293432320, 100519810139548800, 63970355423583984375, 49745967806568479846400, 46413542581052579412480000, 51171212156597654150866636800 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Michael De Vlieger, Table of n, a(n) for n = 1..215 FORMULA a(n) = n^n*Gamma((3*n+1)/2)/Gamma((n+1)/2). - Emeric Deutsch, Jan 23 2006 MAPLE a:=n->n^n*GAMMA(3*n/2+1/2)/GAMMA(n/2+1/2): seq(a(n), n=1..18); # Emeric Deutsch, Jan 23 2006 a:=n->mul(sum (j-k+n, j=1..n), k=1..n): seq(a(n), n=1..13); # Zerinvary Lajos, Jun 04 2007 MATHEMATICA Array[#^#*Gamma[3 #/2 + 1/2]/Gamma[#/2 + 1/2] &, 13] (* Michael De Vlieger, Feb 19 2019 *) PROG (MAGMA) [Round(n^n*Gamma((3*n+1)/2)/Gamma((n+1)/2)): n in [1..15]]; // G. C. Greubel, Feb 20 2019 (Sage) [n^n*gamma((3*n+1)/2)/gamma((n+1)/2) for n in (1..15)] # G. C. Greubel, Feb 20 2019 (PARI) a(n) = prod(k=0, n-1, n*(n+1)/2 + k*n); \\ Michel Marcus, Feb 20 2019 CROSSREFS Cf. A000217. Sequence in context: A081022 A049291 A351180 * A222268 A280179 A223203 Adjacent sequences:  A092955 A092956 A092957 * A092959 A092960 A092961 KEYWORD easy,nonn AUTHOR Amarnath Murthy, Mar 25 2004 EXTENSIONS More terms from Ray G. Opao, Mar 29 2004 More terms from Emeric Deutsch, Jan 23 2006 More terms from Zerinvary Lajos, Jun 04 2007 STATUS approved

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Last modified June 25 19:25 EDT 2022. Contains 354851 sequences. (Running on oeis4.)