A221616 Permutation of the minimal 27 balls of a ball clock after a 12-hour period.

3, 26, 13, 2, 21, 16, 8, 14, 6, 18, 5, 12, 10, 11, 9, 20, 4, 23, 19, 25, 1, 27, 22, 17, 7, 15, 24

Offset

1,1

Comments

The clock has 3 bars with lengths 5, 11, 11. So the minimal number of balls is (5+11+11)+1=27. Use clock(0) PARI script to get the permutation.

Links

Table of n, a(n) for n=1..27.

dott. Roberto Gobbo, Roll-o-clock

Adam Bowman, Ball Clock Gadget

Prog

(PARI) clock(n) = {vb1 = []; vb2 = []; vb3 = []; nb1 = 5; nb2 = 12; nb3 = 12; nbmin = (nb1-1) + (nb2-1) + (nb3-1)+1; vbn = vector(nbmin+n, x, x); nbt = nb1*nb2*nb3; for (i=1, nbt, ib = vbn[1]; vbn = vector(length(vbn)-1, x, vbn[x+1]); vb1 = concat(vb1, ib); if (length(vb1) == nb1, vb2 = concat(vb2, ib); forstep(j=nb1-1, 1, -1, vbn = concat(vbn, vb1[j]); ); vb1 = []; if (length(vb2) == nb2, vb3 = concat(vb3, ib); forstep(j=nb2-1, 1, -1, vbn = concat(vbn, vb2[j]); ); vb2 = []; if (length(vb3) == nb3, vbn = concat(vbn, ib); forstep(j=nb3-1, 1, -1, vbn = concat(vbn, vb3[j]); ); vb3 = []; ); ); ); /* write("clock.log", "vb1=", vb1); write("clock.log", "vb2=", vb2); write("clock.log", "vb3=", vb3); write("clock.log", "vbN=", vbn); write("clock.log", "-----------"); */ ); return (vbn); }

Crossrefs

Cf. A221617.

Sequence in context: A307654 A307653 A326610 * A321222 A062181 A058993

Adjacent sequences: A221613 A221614 A221615 * A221617 A221618 A221619

Keyword

nonn,fini,full

Author

Michel Marcus, Jan 21 2013

Status

approved