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A278597
One half of A278481.
0
1, 2, 2, 2, 3, 2, 2, 3, 3, 2, 2, 3, 3, 3, 2, 2, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2
OFFSET
1,2
COMMENTS
Apart from the left border and the right border, the rest of the elements are 3's.
FORMULA
a(n) = A278481(n)/2.
EXAMPLE
The sequence written as a triangle begins:
1;
2, 2;
2, 3, 2;
2, 3, 3, 2;
2, 3, 3, 3, 2;
2, 3, 3, 3, 3, 2;
2, 3, 3, 3, 3, 3, 2;
2, 3, 3, 3, 3, 3, 3, 2;
2, 3, 3, 3, 3, 3, 3, 3, 2;
2, 3, 3, 3, 3, 3, 3, 3, 3, 2;
...
CROSSREFS
Row sums give A016777.
Left border gives A040000, the same as the right border.
Middle column gives A122553.
Every diagonal that is parallel to any of the borders gives the elements greater than 1 of A158799.
Cf. A278481.
Sequence in context: A160493 A053760 A223942 * A138789 A129654 A116504
KEYWORD
nonn,tabl
AUTHOR
Omar E. Pol, Nov 23 2016
STATUS
approved