This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A070260 Third diagonal of triangle defined in A051537. 3
 3, 2, 15, 6, 35, 12, 63, 20, 99, 30, 143, 42, 195, 56, 255, 72, 323, 90, 399, 110, 483, 132, 575, 156, 675, 182, 783, 210, 899, 240, 1023, 272, 1155, 306, 1295, 342, 1443, 380, 1599, 420, 1763, 462, 1935, 506, 2115, 552, 2303, 600, 2499, 650, 2703, 702 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Colin Barker, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (0,3,0,-3,0,1). FORMULA From Vladeta Jovovic, May 09 2002: (Start) a(n) = n*(n+2)/4 if n is even else n*(n+2). a(n) = 3*a(n-2) - 3*a(n-4) + a(n-6). G.f.: x*(3 + 2*x + 6*x^2 - x^4)/(1 - x^2)^3. (End) E.g.f.: (x/4)*((12 + x)*cosh(x) + (3 + 4*x)*sinh(x)). - G. C. Greubel, Jul 20 2017 MATHEMATICA Table[ LCM[i + 2, i] / GCD[i + 2, i], {i, 1, 60}] PROG (PARI) Vec(x*(3+2*x+6*x^2-x^4) / (1-x^2)^3 + O(x^60)) \\ Colin Barker, Mar 27 2017 CROSSREFS Bisections: A002378, A000466. Sequence in context: A086485 A068310 A033314 * A142705 A072346 A103236 Adjacent sequences:  A070257 A070258 A070259 * A070261 A070262 A070263 KEYWORD nonn,easy AUTHOR Amarnath Murthy, May 09 2002 EXTENSIONS More terms from Vladeta Jovovic, May 09 2002 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 August 19 18:51 EDT 2019. Contains 326133 sequences. (Running on oeis4.)