A072937 Least k such that prime(n) appears in factorization of k! + 1.

2, 4, 3, 5, 12, 16, 9, 14, 18, 30, 36, 40, 21, 23, 52, 15, 8, 18, 7, 72, 23, 13, 88, 96, 100, 6, 106, 86, 112, 63, 65, 16, 16, 50, 150, 156, 81, 166, 172, 89, 180, 95, 102, 196, 99, 210, 222, 61, 228, 64, 210, 240, 97, 31, 131, 9, 93, 40, 280, 282, 45, 63, 220, 312, 91

Offset: 2

Author

Benoit Cloitre, Aug 20 2002

Keywords

• easy
• nonn

Examples

			12!+1 = 13^2*2834329 and 12 is the smallest integer k such that 13 = prime(6) appears in k!+1 factorization, hence a(6)=12
		

Crossrefs

Cf. A073944 (duplicate of this sequence, with an initial term a(1)=1).

Programs

PARI

a(n)=if(n<0,0,s=1; while((s!+1)%prime(n)>0,s++); s)