A063177 Triangular spiral sequence: sequence is written as a triangular spiral, each entry is the sum of the row in the previous direction containing the previous entry.

1, 1, 2, 2, 5, 6, 6, 19, 22, 23, 23, 93, 101, 108, 110, 110, 545, 573, 601, 626, 632, 632, 3719, 3848, 3978, 4102, 4218, 4241, 4241, 28979, 29704, 30431, 31140, 31823, 32478, 32588, 32588, 253972, 258758, 263549, 268252, 272856, 277336, 281687

Offset

1,3

Links

Table of n, a(n) for n=1..44.

F.M. van Lamoen, Spiral recurrence.

Example

The spiral starts
                       110
                       / \
                      /   \
                    545   110
                    /       \
                   /         \
                 573    2    108
                 /     / \     \
                /     /   \     \
              601    5     2    101
              /     /       \     \
             /     /         \     \
           626    6     1-----1    93
           /     /                   \
          /     /                     \
        632    6----19----22----23----23

Crossrefs

Cf. A062410, A063178.

Sequence in context: A209465 A209527 A054255 * A249521 A355345 A034803

Adjacent sequences: A063174 A063175 A063176 * A063178 A063179 A063180

Keyword

nonn,nice

Author

Floor van Lamoen, Jul 09 2001

Status

approved