OFFSET
0,12
COMMENTS
In other words, a(n) is the number of ways to write n as the sum of two binary anagrams.
Leading zeros are ignored.
LINKS
Rémy Sigrist, Table of n, a(n) for n = 0..16384
Rémy Sigrist, PARI program for A331216
Rémy Sigrist, Scatterplot of (x, y) such that 0 <= x, y <= 2^10 and x and y are binary anagrams (a(n) corresponds to the number of pixels (x, y) such that x+y = n)
FORMULA
a(2*n) > 0.
a(2*n) >= a(n).
Apparently, a(3*2^k-1-x) = a(3*2^k-1+x) for any k >= 0 and x = -2^k..2^k.
EXAMPLE
For n = 22:
- we can write 22 as u + v in the following ways:
u v bin(u) bin(v)
-- -- ------ ------
10 12 1010 1100
11 11 1011 1011
12 10 1100 1010
- hence a(22) = 3.
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Jan 12 2020
STATUS
approved