

A185586


EKG sequence (A064413) written clockwise as a square spiral and read counterclockwise.


2



2, 1, 6, 4, 18, 15, 5, 10, 8, 12, 9, 3, 24, 21, 7, 14, 36, 39, 13, 26, 28, 35, 25, 30, 27, 33, 11, 22, 20, 16, 38, 42, 51, 17, 34, 32, 58, 70, 65, 55, 60, 63, 49, 56, 54, 52, 50, 48, 69, 23, 46, 44, 40, 45, 57, 19, 64, 72, 93, 31, 62, 66, 87, 29, 141, 47, 94, 92, 100
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OFFSET

1,1


COMMENTS

A permutation of the natural numbers.
The subsequence of primes (A000040) begins: 2, 5, 3, 7, 13, 11, 17, 23, 19, 31, 29, 47, 43, 41, 37, 53, ...


LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..10000
J. C. Lagarias, E. M. Rains and N. J. A. Sloane, The EKG sequence, Exper. Math. 11 (2002), 437446.
J. C. Lagarias, E. M. Rains and N. J. A. Sloane, The EKG Sequence
I. Peterson, The EKG Sequence
Eric Weisstein's World of Mathematics, EKG Sequence
Index entries for sequences related to EKG sequence
Index entries for sequences that are permutations of the natural numbers


EXAMPLE

1,2,4,6,3,9,12,8,10,5,15,18,... are written clockwise as a square spiral, then read counterclockwise: 2,1,6,4,18,15,5,10,8,12,9,3,...
The square spiral begins:
33 27 30 25 35 28
11 12 8 10 5 26
22 9 1 2 15 13
20 3 6 4 18 39
16 24 21 7 14 36
38 42 51 17 34 32


CROSSREFS

Cf. A064413.
Sequence in context: A121403 A155550 A005299 * A128728 A084950 A180317
Adjacent sequences: A185583 A185584 A185585 * A185587 A185588 A185589


KEYWORD

nonn


AUTHOR

Paul Curtz, Feb 04 2011


STATUS

approved



