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 A351962 Square array A(n,k) = A156552(lcm(A005940(1+n), A005940(1+k))), read by antidiagonals. 4
 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, 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, 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 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS 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. LINKS Table of n, a(n) for n=0..90. Index entries for sequences related to binary expansion of n Index entries for sequences related to lcm's EXAMPLE The top left corner of the array: n=0 1 2 3 4 5 6 7 8 9 10 11 12 -----|----------------------------------------------------------- k= 0 | 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1 | 1, 1, 5, 3, 9, 5, 13, 7, 17, 9, 21, 11, 25, 2 | 2, 5, 2, 11, 10, 5, 6, 23, 18, 21, 10, 11, 26, 3 | 3, 3, 11, 3, 19, 11, 27, 7, 35, 19, 43, 11, 51, 4 | 4, 9, 10, 19, 4, 21, 22, 39, 20, 9, 10, 43, 12, 5 | 5, 5, 5, 11, 21, 5, 13, 23, 37, 21, 21, 11, 53, 6 | 6, 13, 6, 27, 22, 13, 6, 55, 38, 45, 22, 27, 54, 7 | 7, 7, 23, 7, 39, 23, 55, 7, 71, 39, 87, 23, 103, 8 | 8, 17, 18, 35, 20, 37, 38, 71, 8, 41, 42, 75, 44, 9 | 9, 9, 21, 19, 9, 21, 45, 39, 41, 9, 21, 43, 25, 10 | 10, 21, 10, 43, 10, 21, 22, 87, 42, 21, 10, 43, 26, 11 | 11, 11, 11, 11, 43, 11, 27, 23, 75, 43, 43, 11, 107, 12 | 12, 25, 26, 51, 12, 53, 54, 103, 44, 25, 26, 107, 12, 13 | 13, 13, 13, 27, 45, 13, 13, 55, 77, 45, 45, 27, 109, 14 | 14, 29, 14, 59, 46, 29, 14, 119, 78, 93, 46, 59, 110, 15 | 15, 15, 47, 15, 79, 47, 111, 15, 143, 79, 175, 47, 207, 16 | 16, 33, 34, 67, 36, 69, 70, 135, 40, 73, 74, 139, 76, PROG (PARI) up_to = 104; A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); }; 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 }; A351962sq(n, k) = A156552(lcm(A005940(1+n), A005940(1+k))); 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); }; v351962 = A351962list(up_to); A351962(n) = v351962[1+n]; CROSSREFS Cf. A003990, A005940, A156552. Cf. A001477 (main diagonal). Cf. also A341520, A351960, A351961. Sequence in context: A363226 A075758 A125596 * A253026 A341145 A204994 Adjacent sequences: A351959 A351960 A351961 * A351963 A351964 A351965 KEYWORD nonn,tabl AUTHOR Antti Karttunen, Feb 26 2022 STATUS approved

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Last modified May 28 00:20 EDT 2024. Contains 372900 sequences. (Running on oeis4.)