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%I #7 Feb 27 2022 22:56:23
%S 0,1,1,2,1,2,3,5,5,3,4,3,2,3,4,5,9,11,11,9,5,6,5,10,3,10,5,6,7,13,5,
%T 19,19,5,13,7,8,7,6,11,4,11,6,7,8,9,17,23,27,21,21,27,23,17,9,10,9,18,
%U 7,22,5,22,7,18,9,10,11,21,21,35,39,13,13,39,35,21,21,11,12,11,10,19,20,23,6,23,20,19,10,11,12
%N Square array A(n,k) = A156552(lcm(A005940(1+n), A005940(1+k))), read by antidiagonals.
%C The indices run as A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), etc. The array is symmetric.
%H <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%H <a href="/index/Lc#lcm">Index entries for sequences related to lcm's</a>
%e The top left corner of the array:
%e n=0 1 2 3 4 5 6 7 8 9 10 11 12
%e -----|-----------------------------------------------------------
%e k= 0 | 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
%e 1 | 1, 1, 5, 3, 9, 5, 13, 7, 17, 9, 21, 11, 25,
%e 2 | 2, 5, 2, 11, 10, 5, 6, 23, 18, 21, 10, 11, 26,
%e 3 | 3, 3, 11, 3, 19, 11, 27, 7, 35, 19, 43, 11, 51,
%e 4 | 4, 9, 10, 19, 4, 21, 22, 39, 20, 9, 10, 43, 12,
%e 5 | 5, 5, 5, 11, 21, 5, 13, 23, 37, 21, 21, 11, 53,
%e 6 | 6, 13, 6, 27, 22, 13, 6, 55, 38, 45, 22, 27, 54,
%e 7 | 7, 7, 23, 7, 39, 23, 55, 7, 71, 39, 87, 23, 103,
%e 8 | 8, 17, 18, 35, 20, 37, 38, 71, 8, 41, 42, 75, 44,
%e 9 | 9, 9, 21, 19, 9, 21, 45, 39, 41, 9, 21, 43, 25,
%e 10 | 10, 21, 10, 43, 10, 21, 22, 87, 42, 21, 10, 43, 26,
%e 11 | 11, 11, 11, 11, 43, 11, 27, 23, 75, 43, 43, 11, 107,
%e 12 | 12, 25, 26, 51, 12, 53, 54, 103, 44, 25, 26, 107, 12,
%e 13 | 13, 13, 13, 27, 45, 13, 13, 55, 77, 45, 45, 27, 109,
%e 14 | 14, 29, 14, 59, 46, 29, 14, 119, 78, 93, 46, 59, 110,
%e 15 | 15, 15, 47, 15, 79, 47, 111, 15, 143, 79, 175, 47, 207,
%e 16 | 16, 33, 34, 67, 36, 69, 70, 135, 40, 73, 74, 139, 76,
%o (PARI)
%o up_to = 104;
%o A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
%o A156552(n) = { my(f = factor(n), p, p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res };
%o A351962sq(n,k) = A156552(lcm(A005940(1+n),A005940(1+k)));
%o A351962list(up_to) = { my(v = vector(1+up_to), i=0); for(a=0,oo, for(col=0,a, i++; if(i > #v, return(v)); v[i] = A351962sq(col,(a-(col))))); (v); };
%o v351962 = A351962list(up_to);
%o A351962(n) = v351962[1+n];
%Y Cf. A003990, A005940, A156552.
%Y Cf. A001477 (main diagonal).
%Y Cf. also A341520, A351960, A351961.
%K nonn,tabl
%O 0,4
%A _Antti Karttunen_, Feb 26 2022
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