This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A198895 Triangle of coefficients arising in expansion of n-th derivative of tan(x) + sec(x). 0
 1, 1, 1, 1, 2, 1, 1, 4, 5, 2, 1, 8, 18, 16, 5, 1, 16, 58, 88, 61, 16, 1, 32, 179, 416, 479, 272, 61, 1, 64, 543, 1824, 3111, 2880, 1385, 272, 1, 128, 1636, 7680, 18270, 24576, 19028, 7936, 1385, 1, 256, 4916, 31616, 101166, 185856, 206276 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 LINKS Shi-Mei Ma, Derivative polynomials and permutations by numbers of interior peaks and left peaks, 2011. arXiv:1106.5781 FORMULA n-th row represents the coefficients of the polynomial R_n(x) defined by the recurrence: R_0(x) = 1, R_1(x) = 1+x, and for n>=1, R_{n+1}(x) = (1+n*x^2)*R_n(x) + x*(1-x^2)*R'_n(x). EXAMPLE Triangle begins 1 1 1 1 2 1 1 4 5 2 1 8 18 16 5 1 16 58 88 61 16 1 32 179 416 479 272 61 ... CROSSREFS Cf. A098558 (row sums?), A000111 (diagonal and 1st subdiagonal), A000340 (column 3) A000431 (column 4), A000363 (column 5) Sequence in context: A263284 A158471 A158472 * A118686 A102610 A203300 Adjacent sequences:  A198892 A198893 A198894 * A198896 A198897 A198898 KEYWORD nonn,tabl AUTHOR N. J. A. Sloane, Oct 31 2011 EXTENSIONS More terms from Max Alekseyev, Feb 17 2012 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 June 24 22:04 EDT 2019. Contains 324337 sequences. (Running on oeis4.)