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URL: https://oeis.org/A266510

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A266510
Partial sums of A266509.
4
0, 0, 1, 2, 3, 4, 7, 10, 11, 12, 15, 18, 23, 28, 35, 42, 43, 44, 47, 50, 55, 60, 67, 74, 79, 84, 95, 106, 123, 140, 155, 170, 171, 172, 175, 178, 183, 188, 195, 202, 207, 212, 223, 234, 251, 268, 283, 298, 303, 308, 319, 330, 347, 364, 387, 410, 439, 468, 503, 538, 579, 620, 651, 682, 683, 684, 687, 690, 695, 700
OFFSET
1,4
COMMENTS
Also A256265 and twice the terms of A256264 interleaved, with a(1) = 0.
It appears that this sequence has a fractal (or fractal-like) behavior.
First differs from A266530 at a(55), with which it shares infinitely many terms.
First differs from A266540 at a(25), with which it shares infinitely many terms.
For an illustration of initial terms consider the diagram of A256264 in the fourth quadrant of the square grid together with a reflected copy in the second quadrant.
FORMULA
a(2n-1) = A256265(n).
a(2n) = 2 * A256264(n-1).
a(n) = (a(n-1) + a(n+1))/2, if n is an odd number greater than 1.
MATHEMATICA
Accumulate@Riffle[#, #] &@ Flatten@Join[{0}, NestList[Join[#, Range[ Length[ #] - 1]*6 - 1, {2 #[[-1]] + 1}] &, {1}, 5]] (* Ivan Neretin, Feb 14 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Dec 30 2015
STATUS
approved