The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A228461 Two-dimensional array read by antidiagonals: T(n,k) = number of arrays of maxima of three adjacent elements of some length n+2 0..k array. 14
 2, 3, 4, 4, 9, 7, 5, 16, 22, 11, 6, 25, 50, 46, 17, 7, 36, 95, 130, 91, 27, 8, 49, 161, 295, 310, 183, 44, 9, 64, 252, 581, 821, 736, 383, 72, 10, 81, 372, 1036, 1847, 2227, 1821, 819, 117, 11, 100, 525, 1716, 3703, 5615, 6254, 4673, 1749, 189, 12, 121, 715, 2685, 6812 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS There are two arrays (or lists, or vectors) involved, a length n+2 array with free elements from 0..k (thus (k+1)^(n+2) of them) and an array that is being enumerated of length n, each element of the latter being the maximum of three adjacent elements of the first array. Many different first arrays can give the same second array. LINKS R. H. Hardin, Table of n, a(n) for n = 1..1700 FORMULA Empirical for column k: k=1: a(n) = 2*a(n-1) -a(n-2) +a(n-4) k=2: a(n) = 3*a(n-1) -3*a(n-2) +a(n-3) +3*a(n-4) -a(n-5) +a(n-6) +a(n-7) k=3: [order 10] k=4: [order 13] k=5: [order 16] k=6: [order 19] k=7: [order 22] Empirical for row n: n=1: a(n) = n + 1 n=2: a(n) = n^2 + 2*n + 1 n=3: a(n) = (2/3)*n^3 + (5/2)*n^2 + (17/6)*n + 1 n=4: a(n) = (1/3)*n^4 + 2*n^3 + (25/6)*n^2 + (7/2)*n + 1 n=5: a(n) = (2/15)*n^5 + (7/6)*n^4 + (25/6)*n^3 + (19/3)*n^2 + (21/5)*n + 1 n=6: [polynomial of degree 6] n=7: [polynomial of degree 7] EXAMPLE Table starts ...2....3.....4.....5......6......7.......8.......9......10.......11.......12 ...4....9....16....25.....36.....49......64......81.....100......121......144 ...7...22....50....95....161....252.....372.....525.....715......946.....1222 ..11...46...130...295....581...1036....1716....2685....4015.....5786.....8086 ..17...91...310...821...1847...3703....6812...11721...19117....29843....44914 ..27..183...736..2227...5615..12453...25096...46941...82699...138699...223224 ..44..383..1821..6254..17487..42386...92430..185727..349558...623513..1063283 ..72..819..4673.18394..57303.151882..357510..768231.1535578..2893605..5191407 .117.1749.12107.55285.194064.567835.1453506.3357985.7152815.14263777.26930773 Some solutions for n=4 k=4 ..3....4....4....3....3....4....3....4....3....0....3....3....4....2....0....2 ..0....4....1....3....2....0....2....4....1....0....3....3....1....2....0....0 ..4....1....1....0....1....0....4....0....0....0....2....1....4....2....2....3 ..4....0....3....3....2....0....4....2....3....1....3....1....4....0....4....3 CROSSREFS Column 1 is A005252(n+3) Column 2 is A217878 Column 3 is A217949. A228464 is another column. Row 1 is A000027(n+1) Row 2 is A000290(n+1) Row 3 is A002412(n+1) Row 4 is A006324(n+1) See A217883, A217954 for similar arrays. Sequence in context: A269537 A269678 A269467 * A267471 A268457 A244940 Adjacent sequences:  A228458 A228459 A228460 * A228462 A228463 A228464 KEYWORD nonn,tabl AUTHOR R. H. Hardin Aug 22 2013 EXTENSIONS Edited by N. J. A. Sloane, Sep 02 2013 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 May 8 05:23 EDT 2021. Contains 343653 sequences. (Running on oeis4.)