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 A047931 Number of new penny-penny contacts when putting pennies on a table following a spiral pattern. 6

%I #16 Apr 10 2018 08:28:07

%S 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,

%T 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,

%U 3,3,2,3,3,3,3,2,3,3,3,3,2,3,3,3,3,2,3,3,3,3,3

%N Number of new penny-penny contacts when putting pennies on a table following a spiral pattern.

%H R. W. Grosse-Kunstleve, <a href="http://web.archive.org/web/20050425075654/http://cci.lbl.gov/~rwgk/EIS/PennySpiral.html">Penny Spiral Sequence</a>

%F 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.

%e From _Omar E. Pol_, Nov 16 2016: (Start)

%e The sequence written as a spiral begins:

%e .

%e . 2 - 3 - 3 - 3 - 3 - 2

%e . / \

%e . 3 2 - 3 - 3 - 3 - 2 3

%e . / / \ \

%e . 3 3 2 - 3 - 3 - 2 3 3

%e . / / / \ \ \

%e . 3 3 3 2 - 3 - 2 3 3 3

%e . / / / / \ \ \ \

%e . 3 3 3 3 2 - 2 3 3 3 3

%e . / / / / / \ \ \ \ \

%e . 2 2 2 2 2 0 - 1 2 2 2 2

%e . \ \ \ \ \ / / / /

%e . 3 3 3 3 2 - 3 - 2 3 3 3

%e . \ \ \ \ / / /

%e . 3 3 3 2 - 3 - 3 - 2 3 3

%e . \ \ \ / /

%e . 3 3 2 - 3 - 3 - 3 - 2 3

%e . \ \ /

%e . 3 2 - 3 - 3 - 3 - 3 - 2

%e . \

%e . 2 - 3 - 3 - 3 - 3 - 3

%e (End)

%Y Cf. A047932.

%K nonn

%O 1,3

%A _Ralf W. Grosse-Kunstleve_

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Last modified December 7 11:41 EST 2023. Contains 367656 sequences. (Running on oeis4.)