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

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

Crossrefs

Cf. A051953, A083538-A083555, A049586.

Sequence in context: A320195 A129163 A083549 * A082849 A211882 A284432

Adjacent sequences: A083545 A083546 A083547 * A083549 A083550 A083551

Keyword

nonn

Author

Labos Elemer, May 22 2003

Status

approved