A170822 Let p = n-th prime; a(n) = (p-1)/(order of A170821(n) mod p).

1, 3, 2, 2, 1, 1, 2, 1, 1, 12, 1, 1, 2, 1, 2, 4, 1, 14, 2, 1, 2, 1, 2, 1, 1, 2, 2, 1, 1, 10, 1, 3, 1, 1, 4, 9, 2, 1, 2, 18, 2, 16, 1, 1, 1, 1, 2, 2, 1, 2, 6, 2, 1, 2, 1, 1, 2, 1, 1, 1, 3, 10, 12, 1, 1, 42, 2, 12, 1, 2, 1, 4, 27, 2, 1, 4, 1, 6, 2, 6, 10, 4, 3, 2, 1, 2, 1, 1, 2, 2, 1, 2, 3, 2, 1, 5

Offset: 3

Author

N. J. A. Sloane, Dec 24 2009

Keywords

• nonn

Examples

			n=3: p=5, A170821(n)=2, order of 2 mod 5 = 4, (5-1)/4 = 1 = a(3).
		

Links

• I. Anderson and D. A. Preece, Combinatorially fruitful properties of 3*2^(-1) and 3*2^(-2) modulo p, Discr. Math., 310 (2010), 312-324.

Crossrefs

Cf. A001917, A170820, A170821.

Programs

PARI

f(n) = my(p=prime(n), k=0); while(Mod(4*k, p) != 3, k++); k; \\ A170821
a(n) = my(p=prime(n)); (p-1)/znorder(Mod(f(n), p)); \\ Michel Marcus, Dec 04 2018