A100171 Structured triakis octahedral numbers (vertex structure 4).

1, 14, 60, 160, 335, 606, 994, 1520, 2205, 3070, 4136, 5424, 6955, 8750, 10830, 13216, 15929, 18990, 22420, 26240, 30471, 35134, 40250, 45840, 51925, 58526, 65664, 73360, 81635, 90510, 100006, 110144

Offset

1,2

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)=(1/6)*(21*n^3-27*n^2+12*n).

a(0)=1, a(1)=14, a(2)=60, a(3)=160, a(n)=4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4). - Harvey P. Dale, Jun 28 2011

G.f.: (10*x^2+10*x+1)/(x-1)^4. - Harvey P. Dale, Jun 28 2011

Mathematica

Table[(21n^3-27n^2+12n)/6, {n, 40}] (* or *) LinearRecurrence[ {4, -6, 4, -1}, {1, 14, 60, 160}, 40] (* Harvey P. Dale, Jun 28 2011 *)

Prog

(Magma) [(1/6)*(21*n^3-27*n^2+12*n): n in [1..40]]; // Vincenzo Librandi, Jul 27 2011

Crossrefs

Cf. A100157 = alternate vertex; A100145 for more on structured numbers.

Sequence in context: A277986 A261282 A158058 * A063492 A051799 A164540

Adjacent sequences: A100168 A100169 A100170 * A100172 A100173 A100174

Keyword

easy,nonn

Author

James A. Record (james.record(AT)gmail.com), Nov 07 2004

Status

approved