login
A333021
Starts of runs of 4 consecutive even numbers that are all totient numbers (A002202).
6
2, 4, 6, 16, 18, 40, 42, 52, 54, 78, 100, 102, 104, 106, 126, 160, 162, 220, 222, 342, 378, 438, 460, 462, 498, 500, 502, 856, 858, 880, 882, 1086, 1276, 1278, 1300, 1422, 1480, 1482, 1566, 1660, 1662, 1804, 1806, 1996, 2058, 2200, 2202, 2236, 2238, 3016, 3018
OFFSET
1,1
LINKS
EXAMPLE
2 is a term since 2, 4, 6 and 8 are all totient numbers.
PROG
(PARI) m = 4; v = vector(m); for(k=1, m, v[k] = istotient(2*k)); for(k = m+1, 1500, if(Set(v) == [1], print1(2*(k-m), ", ")); v = concat(v[2..m], istotient(2*k)))
KEYWORD
nonn
AUTHOR
Amiram Eldar, Mar 05 2020
STATUS
approved