A225373 a(n) = 1 + Sum_{i=0..floor(n/2)} phi(n-2*i).
1, 2, 2, 4, 4, 8, 6, 14, 10, 20, 14, 30, 18, 42, 24, 50, 32, 66, 38, 84, 46, 96, 56, 118, 64, 138, 76, 156, 88, 184, 96, 214, 112, 234, 128, 258, 140, 294, 158, 318, 174, 358, 186, 400, 206, 424, 228, 470, 244, 512, 264, 544, 288, 596, 306, 636, 330, 672, 358, 730
Offset: 0
Keywords
Links
- Michelangelo Bucci, Alessandro De Luca, Amy Glen and Luca Q. Zamboni, A connection between palindromic and factor complexity using return words, arXiv:0802.1332 [math.CO], 2008.
Crossrefs
Cf. A000010.
Programs
-
Maple
with(numtheory); f:=n->1+add(phi(n-2*i),i=0..floor(n/2)); [seq(f(n),n=0..100)];
-
Mathematica
Table[1 + Sum[EulerPhi[n - 2 i], {i, 0, Floor[n/2]}], {n, 0, 59}] (* Michael De Vlieger, Dec 17 2016 *)
Formula
a(n) = A106481(n) + 1. - Filip Zaludek, Dec 16 2016
Extensions
Name corrected by Michael De Vlieger, Dec 17 2016
Comments