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A140256 Triangle read by columns: Column k is A014963 aerated with groups of (k-1) zeros. 7
1, 2, 1, 3, 0, 1, 2, 2, 0, 1, 5, 0, 0, 0, 1, 1, 3, 2, 0, 0, 1, 7, 0, 0, 0, 0, 0, 1, 2, 2, 0, 2, 0, 0, 0, 1, 3, 0, 3, 0, 0, 0, 0, 0, 1, 1, 5, 0, 0, 2, 0, 0, 0, 0, 1, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 2, 3, 0, 2, 0, 0, 0, 0, 0, 1, 13, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 7, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

If the row number n is prime, the row consists of T(n,1)=n followed by n-2 zeros and followed by T(n,n)=1.

Similar to A138618.

Row products of nonzero terms in row n, equals n. - Mats Granvik, May 22 2016

LINKS

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

T. Tao, Simons Lecture I: Structure and randomness in Fourier analysis and number theory.

Wikipedia, Fundamental theorem of arithmetic.

FORMULA

T(n,k) = A014963(n/k) = A014963(A126988(n,k)) if k|n, T(n,k)=0 otherwise. 1 <= k <= n.

From Mats Granvik, Apr 10 2016, May 22 2016: (Start)

Limit as s -> 1 of the recurrence: Ts(n, k) = if k = 1 then zeta(s)*(1 - 1/n^(s - 1)) -Sum_{i=2..n} Ts(n, i)/(i)^(s - 1) else if n mod k = 0 then Ts(n/k, 1) else 0 else 0.

For n not equal to k: Limit as s -> 1 of the recurrence: Ts(n, k) = if k = 1 then zeta(s) -Sum_{i=2..n} Ts(n, i)/i^(s - 1) else if n mod k = 0 then Ts(n/k, 1) else 0 else 0.

Limit as s -> 1 of the recurrence: Ts(n, k) = if k = 1 then log(n) -Sum_{i=2..n} Ts(n, i)/i^(s - 1) else if n mod k = 0 then Ts(n/k, 1) else 0 else 0. (End)

[The above sentences need a lot of work!  Parentheses might help. - N. J. A. Sloane, Mar 14 2017]

EXAMPLE

First few rows of the triangle are:

   1;

   2, 1;

   3, 0, 1;

   2, 2, 0, 1;

   5, 0, 0, 0, 1;

   1, 3, 2, 0, 0, 1;

   7, 0, 0, 0, 0, 0, 1;

   2, 2, 0, 2, 0, 0, 0, 1;

   3, 0, 3, 0, 0, 0, 0, 0, 1;

   1, 5, 0, 0, 2, 0, 0, 0, 0, 1;

  11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;

   1, 1, 2, 3, 0, 2, 0, 0, 0, 0, 0, 1;

  ...

Column 2 = (1, 0, 2, 0, 3, 0, 2, 0, 5, 0, 1, 0, 7, ...).

MATHEMATICA

t[n_, k_] /; Divisible[n, k] := Exp[ MangoldtLambda[n/k] ]; t[_, _] = 0; Table[t[n, k], {n, 1, 14}, {k, 1, n}] // Flatten (* Jean-Fran├žois Alcover, Nov 28 2013 *)

(* recurrence *)

Clear[t, s, n, k, z, nn]; z = 1; nn = 14; t[n_, k_] := t[n, k] = If[k == 1, Zeta[s]*(1 - 1/n^(s - 1)) -Sum[t[n, i]/i^(s - 1), {i, 2, n}], If[Mod[n, k] == 0, t[n/k, 1], 0], 0]; A = Table[Table[Limit[t[n, k], s -> z], {k, 1, n}], {n, 1, nn}]; Flatten[Exp[A]*Table[Table[If[Mod[n, k] == 0, 1, 0], {k, 1, n}], {n, 1, nn}]] (* Mats Granvik, Apr 09 2016, May 22 2016 *)

PROG

(Excel) =if(row()>=column(); if(mod(row(); column())=0; lookup(roundup(row()/column(); 0); A000027; A014963); 0); "")

CROSSREFS

Cf. A140255 (row sums), A014963.

Row products without the zero terms produce A000027. [Mats Granvik, Oct 08 2009]

Sequence in context: A182740 A228786 A140699 * A126206 A119709 A253556

Adjacent sequences:  A140253 A140254 A140255 * A140257 A140258 A140259

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson and Mats Granvik, May 16 2008, Jun 11 2008

STATUS

approved

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Last modified December 11 10:48 EST 2018. Contains 318049 sequences. (Running on oeis4.)