A163100 Triangle giving positive values of A147861.

1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 1, 1, 3, 1, 1, 2, 2, 1, 1, 1, 1, 2, 3, 3, 2, 1, 1, 1, 1, 2, 2, 1, 1, 3, 3, 1, 1, 2, 4, 2, 1, 1, 1, 1, 2, 3, 3, 2, 1, 1, 1, 1, 2, 4, 4, 2, 1, 1, 3, 3, 1, 1, 2, 2, 1, 1, 1, 1, 2, 3, 4, 4, 3, 2, 1, 1, 5, 1, 1, 2, 2, 1, 1, 3, 3, 1, 1, 2, 4, 4, 2, 1, 1, 1, 1, 2

Offset

1,7

Links

Table of n, a(n) for n=1..105.

Omar E. Pol, Determinacion geometrica de los numeros primos y perfectos

Omar E. Pol, Illustration: Divisors and pi(x)

Example

Triangle begins:
1;
1,1;
1,..1;
1,2,..1;
1,......1;
1,2,2,....1;
1,..........1;
1,2,..2,......1;
1,..3,..........1;
1,2,....2,........1;
1,..................1;
1,2,3,3,..2,..........1;
1,......................1;
1,2,........2,............1;
1,..3,..3,..................1;
1,2,..4,......2,..............1;
1,..............................1;
1,2,3,....3,....2,................1;
1,..................................1;
1,2,..4,4,........2,..................1;
1,..3,......3,..........................1;
1,2,................2,....................1;
1,..........................................1;
1,2,3,4,..4,..3,......2,......................1;
1,......5,......................................1;
1,2,....................2,........................1;
1,..3,..........3,..................................1;
1,2,..4,....4,............2,..........................1;
1,......................................................1;
1,2,3,..5,5,......3,........2,............................1;
...
Row sums: A117004.

Maple

A147861 := proc(n, k) if k<=0 or k > n then 0; else if n mod k = 0 then min(k, n/k) ; else 0; fi; fi; end proc: A163100 := proc(n, k) local dvs; dvs := sort(convert(numtheory[divisors](n), list)) ; min( op(k, dvs), n/op(k, dvs)) ; end: for n from 1 to 60 do for k from 1 to numtheory[tau](n) do printf("%d, ", A163100(n, k) ) ; end do; end do: # R. J. Mathar, Aug 01 2009

Crossrefs

Cf. A000005, A008578, A027750, A051731, A117004, A127093, A147861, A161345, A161424, A161835, A162526, A162527, A162528, A162529, A162530, A162531, A162532.

Sequence in context: A030419 A155052 A096284 * A139038 A322812 A259094

Adjacent sequences: A163097 A163098 A163099 * A163101 A163102 A163103

Keyword

easy,nonn,tabf

Author

Omar E. Pol, Jul 20 2009

Extensions

Extended beyond row 12 by R. J. Mathar, Aug 01 2009

Status

approved