OFFSET
2,1
LINKS
Rémy Sigrist, Table of n, a(n) for n = 2..10012 (rows for n = 2..142 flattened)
FORMULA
T(n, k) >= n.
EXAMPLE
Table T(n, k) begins:
2;
3, 4;
4, 4, 4;
5, 8, 9, 23;
6, 6, 6, 8, 6;
7, 7, 9, 7, 9, 21;
8, 8, 8, 8, 8, 8, 8;
9, 9, 9, 9, 9, 9, 9, 15;
10, 10, 10, 10, 15, 21, 21, 52, 152;
11, 11, 11, 11, 11, 11, 11, 15, 15, 11;
12, 12, 12, 12, 12, 21, 21, 12, 12, 21, 153;
13, 13, 13, 13, 13, 21, 21, 28, 17, 21, 53, 21;
...
PROG
(PARI) T(n, k) = { my (x0 = k, y0 = prime(x0), x1 = n, y1 = prime(x1), s = (y1-y0)/(x1-x0), maxp = max(60184, exp(max(y0/x0, s) + 1.1)), x2 = 0, v = -oo); forprime (y2 = 2, 1+maxp, x2++; if (x0 * (y1 - y2) + x1 * (y2 - y0) + x2 * (y0 - y1)==0, v = x2; ); ); return (v); }
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Rémy Sigrist, Sep 28 2024
STATUS
approved