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A307662 Triangle T(i,j=1..i) read by rows which contain the naturally ordered divisors-or-ones of the row number i. 2
1, 1, 2, 1, 1, 3, 1, 2, 1, 4, 1, 1, 1, 1, 5, 1, 2, 3, 1, 1, 6, 1, 1, 1, 1, 1, 1, 7, 1, 2, 1, 4, 1, 1, 1, 8, 1, 1, 3, 1, 1, 1, 1, 1, 9, 1, 2, 1, 1, 5, 1, 1, 1, 1, 10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 2, 3, 4, 1, 6, 1, 1, 1, 1, 1, 12, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 13 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Replace 0 with 1 in A127093. - Omar E. Pol, Apr 21 2019

LINKS

I. V. Serov, Rows n = 1..131 of triangle, flattened

FORMULA

For j=1..floor(i/2), T(i,j)=T(i-j,j).

For j=floor(i/2)+1..i-1, T(i,j)=1.

T(i,i) = i.

Let i = A002024(n) and j = A002260(n):

a(n) = a((i-j-1)*(i-j)/2+j) if j=1..floor(i/2).

a(n) = 1 if j=floor(i/2)+1..i-1.

a(n) = i if j=i.

T(i,j) = a(n).

EXAMPLE

Triangle begins:

  1,

  1, 2,

  1, 1, 3,

  1, 2, 1, 4,

  1, 1, 1, 1, 5,

  1, 2, 3, 1, 1, 6,

  1, 1, 1, 1, 1, 1, 7,

  1, 2, 1, 4, 1, 1, 1, 8,

  1, 1, 3, 1, 1, 1, 1, 1, 9,

  1, 2, 1, 1, 5, 1, 1, 1, 1,10,

  1, 1, 1, 1, 1, 1, 1, 1, 1, 1,11,

  1, 2, 3, 4, 1, 6, 1, 1, 1, 1, 1,12,

  ...

MATHEMATICA

Table[Map[If[Mod[n, #] == 0, #, 1] &, Range@ n], {n, 13}] // Flatten (* Michael De Vlieger, Apr 23 2019 *)

PROG

(PARI) row(n) = vector(n, k, if ((n % k) == 0, k, 1)); \\ Michel Marcus, Apr 21 2019

CROSSREFS

Cf. A100995, A127093, A307641, A027750, A002024, A002260.

Sequence in context: A112377 A277760 A127704 * A050873 A324668 A128221

Adjacent sequences:  A307659 A307660 A307661 * A307663 A307664 A307665

KEYWORD

nonn,tabl

AUTHOR

I. V. Serov, Apr 20 2019

STATUS

approved

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Last modified August 11 08:05 EDT 2020. Contains 336422 sequences. (Running on oeis4.)