A085885 Let r and s be such that r + s = n; a(n) = maximum value of phi(r) + phi(s).

2, 2, 3, 3, 5, 5, 7, 7, 8, 8, 11, 11, 13, 13, 14, 14, 17, 17, 19, 19, 20, 20, 23, 23, 24, 24, 26, 24, 29, 29, 31, 31, 32, 32, 34, 32, 37, 37, 38, 38, 41, 41, 43, 43, 44, 44, 47, 47, 48, 48, 50, 48, 53, 53, 54, 54, 56, 54, 59, 59, 61, 61, 62, 62, 64, 62, 67, 67, 68, 68, 71, 71, 73

Offset

2,1

Links

Harvey P. Dale, Table of n, a(n) for n = 2..1000

Example

a(8) = 7, the partitions are ( 1,7),(2,6),(3,5),(4,4) which give 7, 3, 6,4 as the sum of phi functions of both the parts.

Mathematica

Table[Max[EulerPhi[#[[1]]]+EulerPhi[#[[2]]]&/@IntegerPartitions[n, {2}]], {n, 2, 80}] (* Harvey P. Dale, Mar 01 2025 *)

Crossrefs

Sequence in context: A035032 A121260 A121261 * A309685 A309683 A283529

Adjacent sequences: A085882 A085883 A085884 * A085886 A085887 A085888

Keyword

nonn,changed

Author

Amarnath Murthy, Jul 08 2003

Extensions

More terms from David Wasserman, Feb 10 2005

Status

approved