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%I #6 Nov 02 2022 07:46:03
%S 0,4,20,40,100,172,248,336,568,820,1100,1400,1692,2012,2352,2720,3632,
%T 4580,5572,6600,7700,8844,10024,11248,12392,13588,14844,16152,17484,
%U 18876,20320,21824,25440,29124,32884,36712,40644,44652,48728,52880
%N Row sums of A163357 and A163359.
%C All terms seem to be divisible by 4. Cf. A163477.
%H Hsien-Kuei Hwang, Svante Janson, and Tsung-Hsi Tsai, <a href="https://arxiv.org/abs/2210.10968">Identities and periodic oscillations of divide-and-conquer recurrences splitting at half</a>, arXiv:2210.10968 [cs.DS], 2022, pp. 42-43.
%t nn = 7; s[{n_, k_}, {m_}] := (a[k, n] = m - 1); MapIndexed[s, List @@ HilbertCurve[nn][[1]]]; Total /@ Table[a[n - k, k], {n, 0, nn^2}, {k, n, 0, -1}] (* _Michael De Vlieger_, Nov 01 2022, after _Jean-François Alcover_ at A163357 *)
%Y Cf. A163357, A163359.
%K nonn
%O 0,2
%A _Antti Karttunen_, Jul 29 2009