This site is supported by donations to The OEIS Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A181106 Largest odd number strictly less than a square. 2
 -1, 3, 7, 15, 23, 35, 47, 63, 79, 99, 119, 143, 167, 195, 223, 255, 287, 323, 359, 399, 439, 483, 527, 575, 623, 675, 727, 783, 839, 899, 959, 1023, 1087, 1155, 1223, 1295, 1367, 1443, 1519, 1599, 1679, 1763, 1847, 1935, 2023, 2115, 2207, 2303, 2399, 2499 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The terms are the negatives of A141354 and therefore have the same generating function except the sign. LINKS Colin Barker, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (2,0,-2,1). FORMULA a(n) = n^2 - 2^(n mod 2) = -A141354(n-1). From Colin Barker, Jun 27 2015: (Start) a(n) = n^2 - 1 for n even; a(n) = n^2 - 2 for n odd. a(n) = 2*a(n-1) - 2*a(n-3) + a(n-4). G.f.: x*(x^3-x^2-5*x+1) / ((x-1)^3*(x+1)). (End) MATHEMATICA Table[n^2-2^Mod[n, 2], {n, 50}] (* Ray Chandler, Dec 05 2011*) LinearRecurrence[{2, 0, -2, 1}, {-1, 3, 7, 15}, 50] (* Harvey P. Dale, Nov 16 2019 *) PROG (PARI) Vec(x*(x^3-x^2-5*x+1)/((x-1)^3*(x+1)) + O(x^100)) \\ Colin Barker, Jun 27 2015 CROSSREFS Equals minus A141354. Cf. A120413 (Largest even number strictly less than a square). Sequence in context: A187220 A067317 A141354 * A131753 A171503 A326354 Adjacent sequences:  A181103 A181104 A181105 * A181107 A181108 A181109 KEYWORD easy,sign,changed AUTHOR Jerzy Kocik (jkocik(AT)siu.edu), Oct 03 2010 EXTENSIONS Edited by Ray Chandler, Dec 05 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 November 18 07:22 EST 2019. Contains 329252 sequences. (Running on oeis4.)