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 A083549 Quotient if least common multiple (lcm) of cototient values of consecutive integers is divided by the greatest common divisor (gcd) of the same pair of consecutive numbers. 1
 0, 1, 2, 2, 4, 4, 4, 12, 2, 6, 8, 8, 8, 56, 56, 8, 12, 12, 12, 12, 12, 12, 16, 80, 70, 126, 144, 16, 22, 22, 16, 208, 234, 198, 264, 24, 20, 12, 40, 24, 30, 30, 24, 56, 56, 24, 32, 224, 210, 570, 532, 28, 36, 60, 480, 672, 70, 30, 44, 44, 32, 864, 864, 544, 782, 46, 36, 900 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Michael De Vlieger, Table of n, a(n) for n = 1..10000 FORMULA a(n) = lcm(A051953(n), A051952(n+1))/gcd(A051953(n), A051952(n+1)) = lcm(cototient(n+1), cototient(n))/A049586(n). EXAMPLE n=33: cototient(33) = 33-20 = 13, cototient(34) = 34-16 = 18; lcm(13,18) = 234, gcd(13,18) = 1, so a(34) = 234. MATHEMATICA f[x_] := x-EulerPhi[x]; Table[LCM[f[w+1], f[w]]/GCD[f[w+1], f[w]], {w, 69}] (* Second program: *) Map[Apply[LCM, #]/Apply[GCD, #] &@ Map[# - EulerPhi@ # &, #] &, Partition[Range[69], 2, 1]] (* Michael De Vlieger, Mar 17 2018 *) CROSSREFS Cf. A051953, A083538, A083539, A083540, A083541, A083542, A083543, A083544, A083545, A083546, A083547, A083548, A083549, A083550, A083551, A083552, A083553, A083554, A083555, A049586. Sequence in context: A220287 A320195 A129163 * A083548 A082849 A211882 Adjacent sequences:  A083546 A083547 A083548 * A083550 A083551 A083552 KEYWORD nonn AUTHOR Labos Elemer, May 22 2003 STATUS approved

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Last modified January 20 08:54 EST 2022. Contains 350471 sequences. (Running on oeis4.)