A333021 Starts of runs of 4 consecutive even numbers that are all totient numbers (A002202).

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

Author

Amiram Eldar, Mar 05 2020

Keywords

• nonn

Examples

			2 is a term since 2, 4, 6 and 8 are all totient numbers.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000
• Wikipedia, Totient numbers.

Crossrefs

Cf. A000010, A002202, A005277, A063512, A083533, A333019, A333020, A333022, A333023, A333024.

Programs

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)))