A115302 Permutation of natural numbers generated by 3-rowed array shown below.

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

Links

Table of n, a(n) for n=1..63.

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

Cf. A088520, A090243, A090298, A143097.

Sequence in context: A138754 A021963 A131914 * A109857 A194075 A271479

Adjacent sequences: A115299 A115300 A115301 * A115303 A115304 A115305

Keyword

easy,nonn

Author

Giovanni Teofilatto, Mar 05 2006

Status

approved