OFFSET
1,2
LINKS
G. C. Greubel, Rows n = 1..50 of the triangle, flattened
FORMULA
EXAMPLE
First few rows of the triangle =
1;
3, 9;
4, 12, 16;
7, 21, 28, 49;
6, 18, 24, 42, 36;
12, 36, 48, 84, 72, 144;
8, 24, 32, 56, 48, 96, 64;
15, 45, 60, 105, 90, 180, 120, 225;
13, 39, 52, 91, 78, 156, 104, 195, 169;
...
T(6,3) = 48 = sigma(6)*sigma(3) = 12*4
MATHEMATICA
A143237[n_, k_]:= DivisorSigma[1, n]*DivisorSigma[1, k];
Table[A143237[n, k], {n, 15}, {k, n}]//Flatten (* G. C. Greubel, Sep 12 2024 *)
PROG
(Magma)
A143237:= func< n, k | DivisorSigma(1, n)*DivisorSigma(1, k) >;
[A143237(n, k): k in [1..n], n in [1..15]]; // G. C. Greubel, Sep 12 2024
(SageMath)
def A143237(n, k): return sigma(n, 1)*sigma(k, 1)
flatten([[A143237(n, k) for k in range(1, n+1)] for n in range(1, 16)]) # G. C. Greubel, Sep 12 2024
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Aug 01 2008
EXTENSIONS
New title by G. C. Greubel, Sep 12 2024
STATUS
approved