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A265500
Balance scale sequence.
0
1, 2, 7, 21, 52, 167, 501, 1503, 4509, 13527, 40581
OFFSET
1,2
COMMENTS
Every natural number up to sum(a[1], a[i]) can be written as adding or subtracting unique entries up to a(i).
LINKS
FORMULA
a(i+1)= 1+2*sum(a[1], a[i]) (proved).
EXAMPLE
17 = 21-7+1+2, 18=21-1-2, 19=17+2.
CROSSREFS
Sequence in context: A352017 A265316 A079034 * A212338 A246861 A305601
KEYWORD
nonn,more
AUTHOR
Ben Paul Thurston, Dec 09 2015
STATUS
approved