The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A086601 Triangular numbers + 1 squared. 6
 1, 4, 16, 49, 121, 256, 484, 841, 1369, 2116, 3136, 4489, 6241, 8464, 11236, 14641, 18769, 23716, 29584, 36481, 44521, 53824, 64516, 76729, 90601, 106276, 123904, 143641, 165649, 190096, 217156, 247009, 279841, 315844, 355216, 398161 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Also number of n X 2 0..1 arrays with rows and columns unimodal (cf. A223620, column 2). - Georg Fischer, Nov 03 2021 LINKS Harvey P. Dale, Table of n, a(n) for n = 0..1000 R. J. Mathar, The number of binary nxm matrices with at most k 1's in each row or column, (2014) Table 2 column 2. Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1). FORMULA a(n) = (A000217(n) + 1)^2. a(n) = (binomial(2+n,2) - binomial(n,1))^2. - Zerinvary Lajos, May 30 2006, corrected by R. J. Mathar, May 14 2014 a(n) = A000124(n)^2. - Omar E. Pol, Oct 30 2007 a(n) = 1 + A061316(n). Zerinvary Lajos, Apr 25 2008 G.f.: ( -1+x-6*x^2+x^3-x^4 ) / (x-1)^5. - R. J. Mathar, May 14 2014 EXAMPLE a(5) = (t(5)+1)^2 = 16^2 = 256. MAPLE A086601 := proc(n)     (n+2+n^2)^2 /4 ; end proc: seq(A086601(n), n=0..20) ; # R. J. Mathar, May 14 2014 MATHEMATICA (Accumulate[Range[0, 40]]+1)^2 (* or *) LinearRecurrence[{5, -10, 10, -5, 1}, {1, 4, 16, 49, 121}, 40] (* Harvey P. Dale, Jan 14 2020 *) PROG (PARI) w=vector(40, i, (t(i)+1)^2) CROSSREFS Cf. A000124, A000217, A061316, A223620. Sequence in context: A222936 A119005 A237986 * A224147 A227266 A114185 Adjacent sequences:  A086598 A086599 A086600 * A086602 A086603 A086604 KEYWORD nonn,easy AUTHOR Jon Perry, Jul 23 2003 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified July 4 10:11 EDT 2022. Contains 355075 sequences. (Running on oeis4.)