login
A047931
Number of new penny-penny contacts when putting pennies on a table following a spiral pattern.
6
0, 1, 2, 2, 2, 2, 3, 2, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 3, 2, 3, 2, 3, 3, 2, 3, 3, 2, 3, 3, 2, 3, 3, 2, 3, 3, 3, 2, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 3, 2, 3, 3, 3, 3, 2, 3, 3, 3, 3, 2, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3
OFFSET
1,3
FORMULA
The n-th "chunk" consists of 2 3{n-2} 2 3{n-1} 2 3{n-1} 2 3{n-1} 2 3{n-1} 2 3{n}, where a{b} symbolizes b repetitions of a.
EXAMPLE
From Omar E. Pol, Nov 16 2016: (Start)
The sequence written as a spiral begins:
.
. 2 - 3 - 3 - 3 - 3 - 2
. / \
. 3 2 - 3 - 3 - 3 - 2 3
. / / \ \
. 3 3 2 - 3 - 3 - 2 3 3
. / / / \ \ \
. 3 3 3 2 - 3 - 2 3 3 3
. / / / / \ \ \ \
. 3 3 3 3 2 - 2 3 3 3 3
. / / / / / \ \ \ \ \
. 2 2 2 2 2 0 - 1 2 2 2 2
. \ \ \ \ \ / / / /
. 3 3 3 3 2 - 3 - 2 3 3 3
. \ \ \ \ / / /
. 3 3 3 2 - 3 - 3 - 2 3 3
. \ \ \ / /
. 3 3 2 - 3 - 3 - 3 - 2 3
. \ \ /
. 3 2 - 3 - 3 - 3 - 3 - 2
. \
. 2 - 3 - 3 - 3 - 3 - 3
(End)
CROSSREFS
Cf. A047932.
Sequence in context: A351284 A268317 A234092 * A258571 A033618 A061357
KEYWORD
nonn
STATUS
approved