A104371 Euler's totient of A104365(n) = A104350(n) + 1.

1, 2, 6, 12, 60, 180, 1152, 2520, 7560, 37332, 415800, 1247400, 16118932, 112918900, 564876900, 1109481408, 17645365584, 57890359152, 1099944846000, 5468570553600, 37559092302400, 421791599312500, 9256378099515120, 29207007622737652, 146100174169950000, 1880759745476519040, 5589847741506645552, 39852571442073216768

Offset: 1

Author

Reinhard Zumkeller, Mar 06 2005

Keywords

• nonn

Links

• Max Alekseyev, Table of n, a(n) for n = 1..158 (terms 1..76 terms from Amiram Eldar, terms 142..151 from Tyler Busby)
• Reinhard Zumkeller, Products of largest prime factors of numbers <= n

Crossrefs

Cf. A000010, A104350, A104363, A104365, A104366, A104367, A104368, A104369, A104370, A104372.

Programs

Mathematica

a[n_] := EulerPhi[1 + Product[FactorInteger[k][[-1, 1]], {k, 1, n}]]; Array[a, 76] (* Amiram Eldar, Feb 12 2020 *)

Formula

a(n) = A000010(A104365(n));

a(p) = A104350(p) for primes p.