A270265 Numbers that are values of the totient function (A002202) but not of the reduced totient function (A002174).

1936, 3872, 6348, 7744, 9196, 15004, 15488, 18392, 20812, 21160, 22264, 30008, 35332, 36784, 38416, 41624, 42320, 44528, 51304, 58564, 63916, 65596, 70664, 73084, 73568, 76832, 79420, 81796, 82668, 83248, 84100, 84640, 86152, 96040, 102124, 102608, 109384, 110836

Offset

1,1

Links

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

William D. Banks, John B. Friedlander, Florian Luca, Francesco Pappalardi, and Igor E. Shparlinski, Coincidences in the values of the Euler and Carmichael functions, Acta Arithmetica 122 (2006), 207-234.

Prog

(PARI) isA002174(n) = if(n%2, return(n==1)); my(f=factor(n), pe); for(i=1, #f~, if(n%(f[i, 1]-1)==0, next); pe=f[i, 1]^f[i, 2]; forstep(q=2*pe+1, n+1, 2*pe, if(n%(q-1)==0 && isprime(q), next(2))); return(0)); 1 \\ Charles R Greathouse IV at A002174
is(n) = istotient(n) && !isA002174(n); \\ Amiram Eldar, Nov 30 2024

Crossrefs

Cf. A000010, A002202.

Cf. A002322, A002174.

Cf. A270266.

Sequence in context: A277943 A251945 A340843 * A237010 A256765 A264109

Adjacent sequences: A270262 A270263 A270264 * A270266 A270267 A270268

Keyword

nonn

Author

Michel Marcus, Mar 14 2016

Extensions

More terms from Jinyuan Wang, Feb 13 2020

Status

approved