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 A001505 a(n) = (4n+1)(4n+2)(4n+3). 2
 6, 210, 990, 2730, 5814, 10626, 17550, 26970, 39270, 54834, 74046, 97290, 124950, 157410, 195054, 238266, 287430, 342930, 405150, 474474, 551286, 635970, 728910, 830490, 941094, 1061106, 1190910, 1330890, 1481430, 1642914, 1815726, 2000250, 2196870, 2405970 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Sum_{n>=0} 1/a(n) = log(2)/4 = 0.17328679513998... [Jolley eq. 253. Typo in comment fixed by Jaume Oliver Lafont, Jan 09 2009] REFERENCES Jolley, Summation of Series, Dover (1961) LINKS T. D. Noe, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1). FORMULA G.f.: 6*(1+x)*(x^2+30*x+1) / (x-1)^4. - R. J. Mathar, Apr 02 2011 MATHEMATICA Table[(4n+1)(4n+2)(4n+3), {n, 0, 49}] (* Vladimir Joseph Stephan Orlovsky, Jan 22 2012 *) PROG (MAGMA) [(4*n+1)*(4*n+2)*(4*n+3): n in [0..100]]; // Vincenzo Librandi, Apr 04 2011 (PARI) a(n)=(4*n+1)*(4*n+2)*(4*n+3) \\ Charles R Greathouse IV, Jun 17 2017 CROSSREFS Equals 6 * A015219. Sequence in context: A068969 A094805 A055193 * A084694 A285149 A065945 Adjacent sequences:  A001502 A001503 A001504 * A001506 A001507 A001508 KEYWORD nonn,easy AUTHOR STATUS approved

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