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A357417 Row sums of the triangular array A357431. 2
1, 5, 12, 27, 43, 76, 109, 168, 218, 301, 383, 499, 591, 779, 904, 1153, 1322, 1555, 1817, 2143, 2379, 2790, 3164, 3627, 3957, 4546, 5034, 5599, 6062, 6937, 7456, 8369, 8973, 9896, 10678, 11663, 12430, 13732, 14618, 15920, 16996, 18471, 19570, 20934, 22189, 24080 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
The rows of the triangular array A357431 are chains of numbers that end with the positive terms of A007952.
It appears that lim_{n->oo} a(n)/A002411(n) will converge to a number close to 0.464401.. . - Thomas Scheuerle, Sep 27 2022
LINKS
EXAMPLE
For n = 6, the numbers of the chain that are divisible by 6, 5, 4, 3, 2, and 1 are 6, 10, 12, 15, 16, and 17, these forming row 6 of A357431. The sum of this row is a(6) = 76.
MATHEMATICA
a[n_] := Module[{k = n, s = n, r}, Do[k++; k += If[(r = Mod[k, i]) == 0, 0, i - Mod[k, i]]; s += k, {i, n - 1, 1, -1}]; s]; Array[a, 50] (* Amiram Eldar, Sep 27 2022 *)
PROG
(MATLAB)
function a = A357417( max_n )
for n = 1:max_n
k = [n:-1:1];
for m = 2:length(k)
k(m) = k(m)*(floor(k(m-1)/k(m))+1);
end
a(n) = sum(k);
end
end % Thomas Scheuerle, Sep 27 2022
(PARI) a(n) = my(t=0); sum(k=0, n-1, t++; t+=(-t)%(n-k)); \\ Kevin Ryde, Sep 27 2022
CROSSREFS
Sequence in context: A176448 A078517 A170828 * A229422 A128439 A240187
KEYWORD
nonn
AUTHOR
Tamas Sandor Nagy, Sep 27 2022
STATUS
approved

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Last modified February 26 22:44 EST 2024. Contains 370354 sequences. (Running on oeis4.)