3,2

Such a number exists for n >= 3 due to a theorem of Enge, Hart and Johansson (see the link, p. 11).

Peter Luschny, Table of n, a(n) for n = 3..1000

Andreas Enge, William Hart and Fredrik Johansson, Short addition sequences for theta functions, Journal of Integer Sequences, Vol. 21 (2018), Article 18.2.4. Also available as arXiv:1608.06810 [math.NT].

(A001318(328) - a(328))/2 = (40426 - 174)/2 = 20126 = A001318(231).

Cf. A001318, A305539.

Sequence in context: A196842 A158474 A090452 * A193924 A110439 A327917

Adjacent sequences: A305535 A305536 A305537 * A305539 A305540 A305541

nonn

Peter Luschny, Jun 04 2018

approved