A136040 Classes of the phi iteration for which the smallest number is prime.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 14, 16, 17, 19, 21, 22, 25, 26, 29, 31, 41, 49, 51, 52, 55, 58, 59, 60, 63, 65, 66, 67, 69, 71, 74, 77, 79, 81, 82, 87, 89, 108, 109, 113, 114, 116, 119, 122, 124, 127, 129, 130, 136, 137, 142, 143, 145, 147, 148, 151, 154, 158, 159, 161, 162, 163

Offset: 1

Author

T. D. Noe, Dec 12 2007

Keywords

• nonn

Comments

Rows of A058812 which begin with a prime. The actual primes are in A092873, which is A007755(n+2) for the n in this sequence.

Links

• T. D. Noe, Table of n, a(n) for n=1..288
• T. D. Noe, Primes in classes of the iterated totient function, JIS 11 (2008) 08.1.2
• Harold Shapiro, An arithmetic function arising from the phi function, Amer. Math. Monthly, Vol. 50, No. 1 (1943), 18-30.

Extensions

Added 63 and 159. - T. D. Noe, Nov 18 2008