A083548 - OEIS

A083548

Least common multiple of cototient values of consecutive integers.

0, 1, 2, 2, 4, 4, 4, 12, 6, 6, 8, 8, 8, 56, 56, 8, 12, 12, 12, 36, 36, 12, 16, 80, 70, 126, 144, 16, 22, 22, 16, 208, 234, 198, 264, 24, 20, 60, 120, 24, 30, 30, 24, 168, 168, 24, 32, 224, 210, 570, 532, 28, 36, 180, 480, 672, 210, 30, 44, 44, 32, 864, 864, 544, 782, 46, 36

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OFFSET

1,3

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = lcm(A051953(n), A051953(n+1)).

MATHEMATICA

f[x_] := x-EulerPhi[x] Table[LCM[f[w+1], f[w]], {w, 1, b}]

LCM@@#&/@Partition[Table[n-EulerPhi[n], {n, 70}], 2, 1] (* Harvey P. Dale, Feb 01 2015 *)

PROG

(PARI) a(n)=lcm(n-eulerphi(n), n+1-eulerphi(n+1)) \\ Charles R Greathouse IV, Nov 16 2012