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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.
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%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