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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A100175 Structured triakis tetrahedral numbers (vertex structure 4). 7
 1, 8, 30, 76, 155, 276, 448, 680, 981, 1360, 1826, 2388, 3055, 3836, 4740, 5776, 6953, 8280, 9766, 11420, 13251, 15268, 17480, 19896, 22525, 25376, 28458, 31780, 35351, 39180, 43276, 47648, 52305, 57256, 62510, 68076, 73963, 80180, 86736, 93640, 100901, 108528 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Equals binomial transform of [1, 7, 15, 9, 0, 0, 0, ...] where (1, 7, 15, 9) = row 3 of triangle A038763. - Gary W. Adamson, Jul 19 2008 Equals convolution square of 1, 4, 7, 10, 13, 16, 19, ..., A016777. - Gary W. Adamson, Jul 28 2009 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..10000 Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1). FORMULA a(n) = (3*n^3 - 3*n^2 + 2*n)/2. G.f.: x*(2*x+1)^2 / ( (x-1)^4 ). MATHEMATICA CoefficientList[Series[x (2x+1)^2/((x-1)^4), {x, 0, 50}], x] (* or *) LinearRecurrence[{4, -6, 4, -1}, {0, 1, 8, 30}, 50] (* Harvey P. Dale, Mar 18 2023 *) PROG (Magma) [(3*n^3-3*n^2+2*n)/2: n in [1..50] ]; // Vincenzo Librandi, Aug 02 2011 CROSSREFS Cf. A000578 (alternate vertex), A100145 for more on structured numbers. Cf. A038763. Sequence in context: A131769 A055832 A195753 * A063489 A299284 A348461 Adjacent sequences: A100172 A100173 A100174 * A100176 A100177 A100178 KEYWORD easy,nonn AUTHOR James A. Record (james.record(AT)gmail.com), Nov 07 2004 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 28 04:22 EDT 2023. Contains 365721 sequences. (Running on oeis4.)