A106727 Triangle T(n,k) = (f(n+1)*f(k+1) mod 10), where f(j) = 10 - (prime(j+3) mod 10), read by rows.

9, 7, 1, 1, 3, 9, 9, 7, 1, 9, 3, 9, 7, 3, 1, 1, 3, 9, 1, 7, 9, 3, 9, 7, 3, 1, 7, 1, 7, 1, 3, 7, 9, 3, 9, 1, 9, 7, 1, 9, 3, 1, 3, 7, 9, 7, 1, 3, 7, 9, 3, 9, 1, 7, 1, 1, 3, 9, 1, 7, 9, 7, 3, 1, 3, 9, 9, 7, 1, 9, 3, 1, 3, 7, 9, 7, 1, 9, 1, 3, 9, 1, 7, 9, 7, 3, 1, 3, 9, 1, 9

Offset

0,1

Links

G. C. Greubel, Rows n = 0..50 of the triangle, flattened

Formula

T(n, k) = (f(n+1)*f(k+1) mod 10) where f(j) = 10 - (prime(j+3) mod 10).

Example

Triangle begins:
  9;
  7, 1;
  1, 3, 9;
  9, 7, 1, 9;
  3, 9, 7, 3, 1;
  1, 3, 9, 1, 7, 9;
  3, 9, 7, 3, 1, 7, 1;

Mathematica

f[n_]:= 10 - Mod[Prime[n+3], 10];
Table[Mod[f[n+1]*f[k+1], 10], {n, 0, 15}, {k, 0, n}]//Flatten

Prog

(Sage)
def f(n): return 10 - (nth_prime(n+3)%10)
def A106727(n, k): return (f(n+1)*f(k+1))%10
flatten([[A106727(n, k) for k in (0..n)] for n in (0..15)]) # G. C. Greubel, Sep 10 2021

Crossrefs

Cf. A007652, A072003.

Sequence in context: A341332 A021107 A155691 * A094134 A329117 A309570

Adjacent sequences: A106724 A106725 A106726 * A106728 A106729 A106730

Keyword

nonn,easy,base,less,tabl

Author

Roger L. Bagula, May 14 2005

Status

approved