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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A105770 Expansion of (x^2-x+1)(4x^2+x+1)/((1+x+x^2)(1-x)^3). 1
1, 2, 7, 10, 17, 28, 37, 50, 67, 82, 101, 124, 145, 170, 199, 226, 257, 292, 325, 362, 403, 442, 485, 532, 577, 626, 679, 730, 785, 844, 901, 962, 1027, 1090, 1157, 1228, 1297, 1370, 1447, 1522, 1601, 1684, 1765, 1850, 1939, 2026, 2117, 2212, 2305, 2402, 2503 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

This sequence is "tesrokseq" at the link "Sequences in Context". The identity vesrok = jesrok + lesrok + tesrok holds.

Differs from A002522 (n^2+1) by two every third number.

LINKS

Table of n, a(n) for n=0..50.

Index entries for linear recurrences with constant coefficients, signature (2, -1, 1, -2, 1).

FORMULA

a(n) = n^2 + 1 + [0,0,2] (3-periodic). -- Ralf Stephan, Nov 15 2010.

MATHEMATICA

LinearRecurrence[{2, -1, 1, -2, 1}, {1, 2, 7, 10, 17}, 51] (* Ray Chandler, Sep 23 2015 *)

PROG

Floretion Algebra Multiplication Program, FAMP Code: 4tesrokseq[ - .25'i + 1.25'j - .25'k - .25i' + 1.25j' - .25k' + 1.25'ii' + .25'jj' - .75'kk' + .75'ij' + .25'ik' + .75'ji' - .25'jk' + .25'ki' - .25'kj' + .25e] (Link to Sequences in Context contains further details on the "roktype" used).

CROSSREFS

  Cf. A105771, A105772, A002522.

Sequence in context: A246128 A226830 A059316 * A240469 A257335 A152211

Adjacent sequences:  A105767 A105768 A105769 * A105771 A105772 A105773

KEYWORD

easy,nonn

AUTHOR

Creighton Dement, Apr 18 2005

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 July 22 18:10 EDT 2017. Contains 289671 sequences.