A083536 First differences of noncototients A005278.

16, 8, 16, 2, 6, 28, 14, 16, 6, 8, 4, 12, 8, 16, 2, 14, 16, 4, 12, 4, 10, 12, 16, 6, 2, 6, 16, 2, 6, 12, 16, 14, 4, 2, 16, 4, 6, 14, 8, 10, 8, 24, 30, 4, 4, 8, 8, 28, 2, 12, 2, 2, 10, 8, 8, 4, 14, 4, 12, 30, 8, 16, 2, 14, 14, 6, 2, 10, 8, 16, 2, 6, 2, 14, 26, 6, 8, 8, 14, 10, 16, 8, 8, 22, 2, 28

Offset: 1

Author

Labos Elemer, May 20 2003

Keywords

• nonn

Examples

			Missing terms from A051953 are 10,26,34,50,.. so their difference sequence starts with 16,8,16,...
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A051953, A005278.

Programs

Mathematica

t0[x_] := Table[j, {j, 1, x}] t=Table[w-EulerPhi[w], {w, 1, 10000}]; u=Union[%]; Delete[u-RotateRight[u], 1]; c=Complement[t0[10000], u]; Delete[c-RotateRight[c], 1];

Formula

a(n) = A005278(n+1) - A005278(n).

Extensions

a(84)-a(85) corrected by David Ng, (an error that was noticed by Doug Phillips), Oct 31 2016

a(86) corrected and name simplified by Omar E. Pol, Nov 04 2016