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A307746
Triangle read by rows, obtained by omitting all the 1's from the triangle in A307641 (except for the first row).
4
1, 2, 3, 2, 2, 5, 2, 3, 7, 2, 2, 2, 3, 3, 2, 5, 11, 2, 3, 2, 13, 2, 7, 3, 5, 2, 2, 2, 2, 17, 2, 3, 3, 19, 2, 2, 5, 3, 7, 2, 11, 23, 2, 3, 2, 2, 5, 5, 2, 13, 3, 3, 3, 2, 2, 7, 29, 2, 3, 5, 31, 2, 2, 2, 2, 2, 3, 11, 2, 17, 5, 7, 2, 3, 2, 3, 37, 2, 19, 3, 13
OFFSET
1,2
COMMENTS
Has same shape as the triangle in A027746. The first difference occurs at row 12.
LINKS
Michel Marcus, Rows n=1..3000 of triangle, flattened (first 131 rows from I. V. Serov)
FORMULA
Row(i) = {d|i, A014963(d) > 1} A014963(d).
For i > 1, T(i, A001222(i)) = A088387(i). This is the last term of the i-th row.
EXAMPLE
Triangle begins:
1;
2;
3;
2, 2;
5;
2, 3;
7;
2, 2, 2;
3, 3;
2, 5;
11;
2, 3, 2;
...
PROG
(PARI) f(n)=ispower(n, , &n); if(isprime(n), n, 1); \\ A014963
row(n) = if (n==1, [1], my(d=divisors(n)); select(x->x!=1, vector(#d, k, f(d[k]))));
tabl(nn) = for (n=1, nn, print(row(n))); \\ Michel Marcus, Apr 27 2019
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
I. V. Serov, Apr 26 2019
STATUS
approved