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A111712
Arithmetic mean of the n-th row of triangle mentioned in A111710.
4
1, 3, 6, 10, 16, 22, 31, 39, 51, 61, 76, 88, 106, 120, 141, 157, 181, 199, 226, 246, 276, 298, 331, 355, 391, 417, 456, 484, 526, 556, 601, 633, 681, 715, 766, 802, 856, 894, 951, 991, 1051, 1093, 1156, 1200, 1266, 1312, 1381, 1429, 1501, 1551, 1626, 1678
OFFSET
1,2
FORMULA
a(1)=1, a(2n) = a(2n-1)+2n, a(2n+1)=a(2n)+3n. a(n) = A111711(n)+floor(n/2). - Franklin T. Adams-Watters, May 01 2006
EXAMPLE
a(4) = (8+9+10+13)/4 =10
MATHEMATICA
With[{r = Range[50]}, Accumulate[Join[{1}, Riffle[2*r, 3*r]]]] (* or *)
LinearRecurrence[{1, 2, -2, -1, 1}, {1, 3, 6, 10, 16}, 100] (* Paolo Xausa, Feb 09 2024 *)
PROG
(Haskell)
a111712 n = a111712_list !! (n-1)
a111712_list = scanl (+) 1 a195013_list
-- Reinhard Zumkeller, Apr 06 2015
CROSSREFS
Partial sums of A195013 prepended with 1.
Sequence in context: A283503 A294481 A049697 * A293407 A194144 A330133
KEYWORD
easy,nonn
AUTHOR
Amarnath Murthy, Aug 24 2005
EXTENSIONS
More terms from Franklin T. Adams-Watters, May 01 2006
STATUS
approved