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A115302
Permutation of natural numbers generated by 3-rowed array shown below.
6
1, 4, 2, 7, 5, 3, 10, 8, 6, 13, 11, 9, 16, 14, 12, 19, 17, 15, 22, 20, 18, 25, 23, 21, 28, 26, 24, 31, 29, 27, 34, 32, 30, 37, 35, 33, 40, 38, 36, 43, 41, 39, 46, 44, 42, 49, 47, 45, 52, 50, 48, 55, 53, 51, 58, 56, 54, 61, 59, 57, 64, 62, 60
OFFSET
1,2
COMMENTS
1 4 7 10 13 16 19 22 25...a(n)=3n+1 => A016777
2 5 8 11 14 17 20 23 26...a(n)=3n+2 => A016789
3 6 9 12 15 18 21 24 27...a(n)=3n => A008585
Reversing the direction of the diagonals gives A143097. - Jeremy Gardiner, Oct 14 2012.
REFERENCES
M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988
Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997
FORMULA
For n > 1, a(n+5) = a(n) + 6, iff a(n+5)<a(n): a(n+3k) = a(n) + 3k with k >=1.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Mar 05 2006
STATUS
approved