The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A136392 a(n) = 6*n^2 - 10*n + 5. 6
 1, 9, 29, 61, 105, 161, 229, 309, 401, 505, 621, 749, 889, 1041, 1205, 1381, 1569, 1769, 1981, 2205, 2441, 2689, 2949, 3221, 3505, 3801, 4109, 4429, 4761, 5105, 5461, 5829, 6209, 6601, 7005, 7421, 7849, 8289, 8741, 9205, 9681, 10169 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Binomial transform of [1, 8, 12, 0, 0, 0, ...]. Numbers k such that 6*k-5 is the square of a number of the form 6*k-5, contained in A199859. - _Eleonora Echeverri-Toro_, Nov 29 2011 Central terms of the triangle A033292. - _Reinhard Zumkeller_, Feb 06 2012 Sequence found by reading the line from 1, in the direction 1, 9, ..., in the square spiral whose vertices are the generalized pentagonal numbers A001318. - _Omar E. Pol_, Jul 18 2012 LINKS Table of n, a(n) for n=1..42. John Elias, Illustration: Centered nesting cube frames Index entries for linear recurrences with constant coefficients, signature (3,-3,1). FORMULA a(n) = n*(3n-2) + (n-1)*(3n-5), n > 1. a(n) = n*A016777(n-1) + (n-1)*A016777(n-2). a(n) = a(n-1) + 12*n-16 (with a(1)=1). - _Vincenzo Librandi_, Nov 24 2010 G.f.: x*(1+x)*(1+5*x)/(1-x)^3. - _Colin Barker_, Jan 09 2012 a(n) = 1 + A033580(n-1). - _Omar E. Pol_, Jul 18 2012 a(n) = A059722(n) - A059722(n-1). - _J. M. Bergot_, Nov 02 2012 a(n) = A000567(n-1) + A000567(n). - _Charlie Marion_, May 29 2024 MATHEMATICA Table[6n^2-10n+5, {n, 50}] (* or *) LinearRecurrence[{3, -3, 1}, {1, 9, 29}, 50] (* _Harvey P. Dale_, Mar 05 2023 *) PROG (PARI) a(n)=6*n^2-10*n+5 \\ _Charles R Greathouse IV_, Nov 29 2011 (Haskell) a136392 n = 2 * n * (3*n - 5) + 5 -- _Reinhard Zumkeller_, Feb 06 2012 CROSSREFS Cf. A000567, A016777, A033580, A059722, A201279, A204675. Sequence in context: A031296 A146869 A129397 * A272732 A272740 A162263 Adjacent sequences: A136389 A136390 A136391 * A136393 A136394 A136395 KEYWORD nonn,easy AUTHOR _Gary W. Adamson_, Dec 28 2007 STATUS approved

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

Last modified September 18 07:20 EDT 2024. Contains 375996 sequences. (Running on oeis4.)