A111389 Numbers n such that p(3n) is prime, where p(n) is the number of partitions of n.

1, 2, 12, 44, 56, 62, 72, 122, 139, 166, 175, 182, 245, 251, 275, 362, 432, 526, 712, 831, 834, 836, 856, 909, 957, 1009, 1056, 1114, 1554, 2266, 2486, 2816, 3967, 4340, 5416, 6092, 6837, 6959, 7215, 7255, 7439, 7734, 9655, 10200, 11080, 11324, 11361, 12819

Offset: 1

Author

Parthasarathy Nambi, Nov 09 2005

Keywords

• nonn

Examples

			If n=72 then p(3n) = 15285151248481 (prime).
		

Links

• Max Alekseyev, Table of n, a(n) for n = 1..1669

Crossrefs

Cf. A000041, A046063, A114165, A111389, A111045, A114166, A111036, A114167, A114168, A114169, A114170.

Programs

Mathematica

Select[ Range[13370], PrimeQ[ PartitionsP[3# ]] &] (* Robert G. Wilson v *)

PARI

is(n)=isprime(numbpart(3*n)) \\ Charles R Greathouse IV, Feb 17 2017

Formula

Elements of A046063 which are == 0 (mod 3) divided by 3

Extensions

a(8)-a(48) from Robert G. Wilson v, Nov 11 2005