OFFSET
2,1
COMMENTS
EXAMPLE
Row 2 = [2] because 2*2 = 2 + 2;
Row 3 = [3] because 2*3 = 3 + 3;
Row 4 = [2,3,5] because 2*4 - 2 = 6 = 2*3 and 2*4 = 3 + 5;
Row 5 = [3,5,7} because 2*5 = 3 + 7 = 5 + 5.
The table starts:
2;
3;
2, 3, 5;
3, 5, 7;
2, 5, 7;
2, 3, 5, 7, 11;
3, 5, 7, 11, 13;
3, 5, 7, 11, 13;
2, 3, 5, 7, 11, 13, 17;
2, 3, 5, 7, 11, 13, 17, 19;
2, 3, 5, 7, 11, 13, 17, 19;
2, 3, 5, 7, 11, 13, 17, 19, 23;
3, 5, 11, 13, 17, 23;
2, 7, 11, 13, 17, 19, 23;
2, 3, 5, 11, 13, 17, 19, 23, 29;
PROG
(PARI) isok(k, n) = {if (isprime(2*n-k), pf = factor(k)[, 1]; for (j=1, #pf, if (isprime(2*n-pf[j]), return (1)); ); ); }
row(n) = {my(v = []); for (k=1, 2*n, if (isok(k, n), v = concat(v, 2*n-k))); vecsort(v); } \\ Michel Marcus, Mar 02 2019
CROSSREFS
KEYWORD
nonn,easy,tabf
AUTHOR
Juri-Stepan Gerasimov, Jan 28 2019
STATUS
approved