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A316489 Positive numbers of the form 8*k + 4 that cannot be expressed as the sum of four distinct odd squares. 2
4, 12, 20, 28, 36, 44, 52, 60, 68, 76, 92, 100, 108, 124, 132, 148, 172, 188, 220, 268, 292, 388, 412 (list; graph; refs; listen; history; text; internal format)



There are no more terms through 10^11. It seems extremely unlikely that any more terms exist.

Every odd square is a number of the form 8*k + 1, so every sum of four odd squares is a number of the form 8*k + 4.

A316834 lists all numbers that can be expressed in only one way as the sum of four distinct odd squares.


Table of n, a(n) for n=1..23.


Cf. A316834.

Sequence in context: A328304 A031065 A017113 * A081770 A062876 A301098

Adjacent sequences:  A316486 A316487 A316488 * A316490 A316491 A316492




Jon E. Schoenfield, Jul 27 2018



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Last modified November 30 06:28 EST 2021. Contains 349419 sequences. (Running on oeis4.)