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A119931
Sum of the numbers of the matrix A111490 along a boustrophedon path: a11, a11+a21, a11+a21+a21, etc.
1
1, 2, 3, 4, 6, 7, 8, 10, 11, 12, 13, 15, 18, 20, 21, 22, 24, 27, 28, 29, 30
OFFSET
0,2
REFERENCES
G. Balzarotti and P. P. Lava, Le sequenze di numeri interi, Hoepli, 2008, p. 60.
EXAMPLE
If we rewrite the matrix putting on the top the upper left edge and then we sum the numbers following a boustrophedon path we have:
.........../.1.
........../_____
...........1...1.\
........._________\
......./.1...2...1.
....../______________
.......1...2...1...1.\
....._________________\
.../.1...2...3...2...1.
../_____________________
...1...2...3...1...1...1.
then
1, 1+1, 1+1+1, 1+1+1+1, 1+1+1+1+2, 1+1+1+1+2+1, 1+1+1+1+2+1+1, 1+1+1+1+2+1+1+2, 1+1+1+1+2+1+1+2+1, 1+1+1+1+2+1+1+2+1+1, ...
That is 1, 2, 3, 4, 6, 7, 8, 10, 11, 12, 13, 15, 18, 20, etc.
CROSSREFS
Cf. A119930.
Sequence in context: A039149 A039081 A195128 * A129989 A187572 A184478
KEYWORD
nonn,easy
AUTHOR
STATUS
approved