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!)
 A238374 Row sums of triangle in A204026. 0
 1, 2, 4, 6, 9, 12, 17, 22, 30, 38, 51, 64, 85, 106, 140, 174, 229, 284, 373, 462, 606, 750, 983, 1216, 1593, 1970, 2580, 3190, 4177, 5164, 6761, 8358, 10942, 13526, 17707, 21888, 28653, 35418, 46364, 57310, 75021, 92732, 121389, 150046, 196414, 242782 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Index entries for linear recurrences with constant coefficients, signature (1,1,-1,1,-1). FORMULA G.f.: (1+x)*(1+x^2)/((1-x^2-x^4)*(1-x)). a(n) = a(n-1) + a(n-2) - a(n-3) + a(n-4) - a(n-5), a(0) = 1, a(1) = 2, a(2) = 4, a(3) = 6, a(4) = 9. a(2*n) = A157728(n+5) = A000045(n+5) - 4. a(2*n+1) = 2*A001911(n+1) = 2*A000045(n+4) - 4. EXAMPLE Triangle in A204026 begins: 1;.........................sum = 1 1, 1;......................sum = 2 1, 2, 1;...................sum = 4 1, 2, 2, 1;................sum = 6 1, 2, 3, 2, 1;.............sum = 9 1, 2, 3, 3, 2, 1;..........sum = 12 1, 2, 3, 5, 3, 2, 1;.......sum = 17 1, 2, 3, 5, 5, 3, 2, 1;....sum = 22 1, 2, 3, 5, 8, 5, 3, 2, 1;.sum = 30 MATHEMATICA LinearRecurrence[{1, 1, -1, 1, -1}, {1, 2, 4, 6, 9}, 50] (* Harvey P. Dale, Feb 24 2018 *) CROSSREFS Cf. A000045, A001911, A157728, A204026 Sequence in context: A090631 A001365 A102379 * A133041 A079492 A267161 Adjacent sequences:  A238371 A238372 A238373 * A238375 A238376 A238377 KEYWORD easy,nonn AUTHOR Philippe Deléham, Feb 25 2014 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 23 05:11 EDT 2021. Contains 345395 sequences. (Running on oeis4.)