This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A341628 #9 Dec 22 2024 21:34:14
%S A341628 3,7,5,5,13,7,3,7,31,11,7,5,11,11,13,7,11,13,13,19,17,11,13,13,11,17,
%T A341628 61,19,31,13,31,17,61,19,307,23,13,11,17,13,19,17,23,127,29,7,31,71,
%U A341628 19,19,23,29,29,79,31,13,13,11,2801,23,61,29,181,31,67,37,5,17,31,19,3221,29,307,31,53,37,331,41
%N A341628 Square array A(n,k) = A006530(A341527(A246278(n,k))), read by falling antidiagonals.
%F A341628 A(n,k) = A006530(A341627(n,k)) = A006530(A341527(A246278(n,k))).
%e A341628 The top left corner of the array:
%e A341628 n= 1 2 3 4 5 6 7 8 9 10 11 12 13 14
%e A341628 2n= 2 4 6 8 10 12 14 16 18 20 22 24 26 28
%e A341628 -----+---------------------------------------------------------------------------
%e A341628 1 | 3, 7, 5, 3, 7, 7, 11, 31, 13, 7, 13, 5, 17, 11,
%e A341628 2 | 5, 13, 7, 5, 11, 13, 13, 11, 31, 13, 17, 7, 19, 13,
%e A341628 3 | 7, 31, 11, 13, 13, 31, 17, 71, 11, 31, 19, 13, 23, 31,
%e A341628 4 | 11, 11, 13, 11, 17, 13, 19, 2801, 19, 17, 23, 13, 29, 19,
%e A341628 5 | 13, 19, 17, 61, 19, 19, 23, 3221, 61, 19, 29, 61, 31, 23,
%e A341628 6 | 17, 61, 19, 17, 23, 61, 29, 30941, 307, 61, 31, 19, 37, 61,
%e A341628 7 | 19, 307, 23, 29, 29, 307, 31, 88741, 127, 307, 37, 29, 41, 307,
%e A341628 8 | 23, 127, 29, 181, 31, 127, 37, 911, 79, 127, 41, 181, 43, 127,
%e A341628 9 | 29, 79, 31, 53, 37, 79, 41, 292561, 67, 79, 43, 53, 47, 79,
%e A341628 10 | 31, 67, 37, 421, 41, 67, 43, 732541, 331, 67, 47, 421, 53, 67,
%e A341628 11 | 37, 331, 41, 37, 43, 331, 47, 17351, 67, 331, 53, 41, 59, 331,
%e A341628 12 | 41, 67, 43, 137, 47, 67, 53, 4271, 1723, 67, 59, 137, 61, 67,
%e A341628 13 | 43, 1723, 47, 43, 53, 1723, 59, 579281, 631, 1723, 61, 47, 67, 1723,
%e A341628 14 | 47, 631, 53, 47, 59, 631, 61, 3500201, 61, 631, 67, 53, 71, 631,
%e A341628 15 | 53, 61, 59, 53, 61, 61, 67, 14621, 409, 61, 71, 59, 73, 67,
%e A341628 16 | 59, 409, 61, 281, 67, 409, 71, 5581, 3541, 409, 73, 281, 79, 409,
%e A341628 17 | 61, 3541, 67, 1741, 71, 3541, 73, 181, 97, 3541, 79, 1741, 83, 3541,
%e A341628 18 | 67, 97, 71, 1861, 73, 97, 79, 21491, 71, 97, 83, 1861, 89, 97,
%e A341628 19 | 71, 71, 73, 449, 79, 73, 83, 26881, 5113, 79, 89, 449, 97, 83,
%o A341628 (PARI)
%o A341628 up_to = 105;
%o A341628 A003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ From A003961
%o A341628 A006530(n) = if(n>1, vecmax(factor(n)[, 1]), 1);
%o A341628 A341528(n) = (n*sigma(A003961(n)));
%o A341628 A341529(n) = (sigma(n)*A003961(n));
%o A341628 A341527(n) = denominator(A341528(n) / A341529(n));
%o A341628 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));
%o A341628 A341628sq(row,col) = A006530(A341527(A246278sq(row,col)));
%o A341628 A341628list(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] = A341628sq(col,(a-(col-1))))); (v); };
%o A341628 v341628 = A341628list(up_to);
%o A341628 A341628(n) = v341628[n];
%Y A341628 Cf. A006530, A246278, A341527, A341627.
%Y A341628 Cf. also A341607.
%K A341628 nonn,tabl
%O A341628 1,1
%A A341628 _Antti Karttunen_, Feb 16 2021