%I #17 Jul 22 2021 09:17:02
%S 1,1,2,1,2,0,2,0,2,1,2,0,3,0,2,0,1,0,4,1,3,0,2,0,3,0,1,0,2,0,4,0,2,1,
%T 2,0,4,0,3,0,2,0,3,0,3,0,2,0,4,0,3,1,2,0,5,0,1,0,2,0,6,0,3,0,1,0,3,0,
%U 4,0,2,0,5,1,4,0,2,0,6,0,3,0,2,0,4,0,2,0,3,0,6,0,2,0,1,0,4,0,3
%N Number of ways to express n as p+2a^2; p = 1 or prime, a >= 0.
%H T. D. Noe, <a href="/A046920/b046920.txt">Table of n, a(n) for n=1..10000</a>
%H L. Hodges, <a href="https://www.jstor.org/stable/2690477">A lesser-known Goldbach conjecture</a>, Math. Mag., 66 (1993), 45-47.
%H <a href="/index/Go#Goldbach">Index entries for sequences related to Goldbach conjecture</a>
%o (Haskell)
%o a046920 n = length $ filter ((\x -> x == 1 || a010051 x == 1) . (n -)) $
%o takeWhile (< n) a001105_list
%o -- _Reinhard Zumkeller_, Apr 03 2013
%Y Cf. A042978, A046921, A046922, A046923, A060003, A143539.
%Y Cf. A016067, A008578, A010051, A001105.
%K nonn
%O 1,3
%A _David W. Wilson_