login
This site is supported by donations to The OEIS Foundation.

 

Logo

"Email this user" was broken Aug 14 to 9am Aug 16. If you sent someone a message in this period, please send it again.

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

a(n) = (8*n^2+3*(-1)^n-3)/2; a(n) = -a(n-1) + 8*n^2 - 8*n + 1. -Vincenzo Librandi, Sep 27 2011

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified August 20 13:04 EDT 2017. Contains 290835 sequences.