Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #8 Dec 21 2016 18:45:53
%S 1,2,2,4,4,4,4,8,8,8,8,8,8,8,8,16,16,16,16,16,16,16,16,16,24,24,24,24,
%T 24,24,24,32,32,32,32,32,32,32,32,32,32,40,40,40,40,40,40,48,48,48,48,
%U 48,48,48,48,48,56,56,56,56,56,56,56,64,64,64,64,64,64,64,64,64,64,64,64,72,72,72,72,80,80,80,80,80,80,80,80,80,88,88,88,88,88,88,88,96,96,96,96,96
%N a(n) is the smallest among the natural numbers m with the property that there exists a non-constant quadratic map S^n -> S^m from the n-dimensional sphere to the m-dimensional sphere.
%C Coincides with A053644 until n=24.
%H P. Yiu, <a href="http://dx.doi.org/10.1007/BF02567607">Quadratic Forms between Euclidean Spheres</a>, Manuscripta Math. 83, pp. 171-181 (1994).
%F Uniquely determined by the following: a(2^t + m) = 2^t if 0 <= m < A003484(2^t); a(2^t + m) = 2^t + a(m) if A003484(2^t) <= m < 2^t.
%Y A003484 used in the definition. Cf. A053644.
%K nonn
%O 1,2
%A _Mamuka Jibladze_, Dec 07 2016