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A093918 a(2k-1)=(2k-1)^2+k, a(2k)=6k^2+k+1: Last term in rows of triangle A093915. 5
2, 8, 11, 27, 28, 58, 53, 101, 86, 156, 127, 223, 176, 302, 233, 393, 298, 496, 371, 611, 452, 738, 541, 877, 638, 1028, 743, 1191, 856, 1366, 977, 1553, 1106, 1752, 1243, 1963, 1388, 2186, 1541, 2421, 1702, 2668, 1871, 2927, 2048, 3198, 2233, 3481, 2426, 3776 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Initially defined as "leading diagonal" of the triangle A093915, a(n) is the last term in row n of A093915, i.e. a(n)=A093916(n)+n-1. - M. F. Hasler, Apr 04 2009
LINKS
FORMULA
Equals A093915 o A000217 = A093916 + A023443. - M. F. Hasler, Apr 04 2009
a(n) = (3+(-1)^n+2*n+(5+(-1)^n)*n^2)/4. a(n) = 3*a(n-2)-3*a(n-4)+a(n-6). G.f.: -x*(x^2+2*x+2)*(x^3-x^2+3*x+1) / ((x-1)^3*(x+1)^3). - Colin Barker, Dec 18 2012
MATHEMATICA
LinearRecurrence[{0, 3, 0, -3, 0, 1}, {2, 8, 11, 27, 28, 58}, 50] (* Harvey P. Dale, Oct 22 2013 *)
PROG
(PARI) A093918(n)=if(n%2, n^2, 6*(n\2)^2)+n\2+1 \\ M. F. Hasler, Apr 04 2009
CROSSREFS
Sequence in context: A197540 A089118 A146480 * A332098 A254313 A209429
KEYWORD
nonn,easy
AUTHOR
Amarnath Murthy, Apr 25 2004
EXTENSIONS
Edited and extended beyond a(6) by M. F. Hasler, Apr 04 2009
STATUS
approved

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Last modified March 28 10:55 EDT 2024. Contains 371241 sequences. (Running on oeis4.)