OFFSET
1,1
LINKS
EXAMPLE
The top left corner of the array:
n= 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
2n= 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34
-----+----------------------------------------------------------------------
1 | 2, 2, 1, 2, 5, 3, 7, 2, 3, 5, 11, 2, 13, 1, 5, 2, 17,
2 | 3, 3, 5, 3, 7, 5, 11, 3, 5, 7, 13, 3, 17, 11, 7, 3, 19,
3 | 5, 5, 7, 5, 11, 7, 13, 5, 7, 11, 17, 7, 19, 13, 11, 5, 23,
4 | 7, 7, 11, 7, 13, 11, 17, 7, 11, 13, 19, 11, 23, 17, 13, 7, 29,
5 | 11, 11, 13, 11, 17, 13, 19, 11, 13, 17, 23, 13, 29,*11, 17, 11, 31,
6 | 13, 13, 17, 13, 19, 17, 23, 13, 17, 19, 29,*13, 31, 23, 19, 13, 37,
7 | 17, 17, 19, 17, 23, 19, 29, 17, 19, 23, 31, 19, 37, 29, 23, 17, 41,
8 | 19, 19, 23, 19, 29, 23, 31, 19, 23, 29, 37, 23, 41, 31, 29, 19, 43,
9 | 23, 23, 29, 23, 31, 29, 37, 23, 29, 31, 41, 29, 43, 37, 31, 23, 47,
10 | 29, 29, 31, 29, 37, 31, 41, 29, 31, 37, 43, 31, 47, 41, 37, 29, 53,
11 | 31, 31, 37, 31, 41, 37, 43, 31, 37, 41, 47,*31, 53, 43, 41, 31, 59,
12 | 37, 37, 41, 37, 43, 41, 47, 37, 41, 43, 53, 41, 59, 47, 43, 37, 61,
13 | 41, 41, 43, 41, 47, 43, 53, 41, 43, 47, 59, 43, 61, 53, 47, 41, 67,
14 | 43, 43, 47, 43, 53, 47, 59, 43, 47, 53, 61, 47, 67, 59, 53, 43, 71,
15 | 47, 47, 53, 47, 59, 53, 61, 47, 53, 59, 67, 53, 71, 47, 59, 47, 73,
16 | 53, 53, 59, 53, 61, 59, 67, 53, 59, 61, 71, 59, 73, 67, 61, 53, 79,
17 | 59, 59, 61, 59, 67, 61, 71, 59, 61, 67, 73, 61, 79, 71, 67, 59, 83,
18 | 61, 61, 67, 61, 71, 67, 73, 61, 67, 71, 79, 67, 83, 73, 71, 61, 89,
19 | 67, 67, 71, 67, 73, 71, 79, 67, 71, 73, 83, 71, 89, 79, 73, 67, 97,
20 | 71, 71, 73, 71, 79, 73, 83, 71, 73, 79, 89, 73, 97, 83, 79, 71, 101,
21 | 73, 73, 79, 73, 83, 79, 89, 73, 79, 83, 97, 79, 101, 89, 83, 73, 103,
etc.
Positions where columns are not strictly monotonic are marked with an asterisk (*). See the example section of A341606 for further elaboration.
PROG
(PARI)
up_to = 105;
A246278sq(row, col) = if(1==row, 2*col, my(f = factor(2*col)); for(i=1, #f~, f[i, 1] = prime(primepi(f[i, 1])+(row-1))); factorback(f));
A006530(n) = if(n>1, vecmax(factor(n)[, 1]), 1);
A017666(n) = denominator(sigma(n)/n);
A341607list(up_to) = { my(v = vector(up_to), i=0); for(a=1, oo, for(col=1, a, i++; if(i > up_to, return(v)); v[i] = A341607sq(col, (a-(col-1))))); (v); };
v341607 = A341607list(up_to);
A341607(n) = v341607[n];
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Antti Karttunen, Feb 16 2021
STATUS
approved