This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A195146 Concentric 16-gonal numbers. 12
 0, 1, 16, 33, 64, 97, 144, 193, 256, 321, 400, 481, 576, 673, 784, 897, 1024, 1153, 1296, 1441, 1600, 1761, 1936, 2113, 2304, 2497, 2704, 2913, 3136, 3361, 3600, 3841, 4096, 4353, 4624, 4897, 5184, 5473, 5776, 6081, 6400, 6721, 7056, 7393, 7744, 8097, 8464 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Also concentric hexadecagonal numbers or concentric hexakaidecagonal numbers. Also sequence found by reading the line from 0, in the direction 0, 16, ..., and the same line from 1, in the direction 1, 33, ..., in the square spiral whose vertices are the generalized decagonal numbers A074377. Main axis, perpendicular to A033996 in the same spiral. LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..10000 Index entries for linear recurrences with constant coefficients, signature (2,0,-2,1). FORMULA From Vincenzo Librandi, Sep 27 2011: (Start) a(n) = (8*n^2 + 3*(-1)^n - 3)/2; a(n) = -a(n-1) + 8*n^2 - 8*n + 1. (End) G.f. -x*(1+14*x+x^2) / ( (1+x)*(x-1)^3 ). - R. J. Mathar, Sep 18 2011 PROG (MAGMA) [(8*n^2+3*(-1)^n-3)/2: n in [0..50]]; // Vincenzo Librandi, Sep 27 2011 (PARI) a(n)=(8*n^2+3*(-1)^n-3)/2 \\ Charles R Greathouse IV, Oct 07 2015 CROSSREFS Cf. A016802 and A195315 interleaved. Cf. A032528, A077221, A195142, A195143, A195145, A195147, A195148, A195149. Column 16 of A195040. Sequence in context: A041502 A041500 A132758 * A198275 A041504 A275252 Adjacent sequences:  A195143 A195144 A195145 * A195147 A195148 A195149 KEYWORD nonn,easy AUTHOR Omar E. Pol, Sep 17 2011 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 October 17 08:36 EDT 2019. Contains 328107 sequences. (Running on oeis4.)