A279170 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.

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, 24, 24, 24, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 40, 40, 40, 40, 40, 40, 48, 48, 48, 48, 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

Offset: 1

Author

Mamuka Jibladze, Dec 07 2016

Keywords

• nonn

Comments

Coincides with A053644 until n=24.

Links

• P. Yiu, Quadratic Forms between Euclidean Spheres, Manuscripta Math. 83, pp. 171-181 (1994).

Crossrefs

A003484 used in the definition. Cf. A053644.

Formula

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.