A097527 Least k such that k*P(n)#-P(n+3) and k*P(n)#+P(n+3) are both primes with P(i)=i-th prime and P(i)#=i-th primorial.

5, 3, 1, 1, 3, 2, 12, 2, 2, 29, 69, 33, 15, 9, 28, 8, 111, 121, 55, 92, 4, 269, 89, 138, 57, 102, 39, 113, 81, 79, 155, 85, 647, 482, 369, 29, 295, 81, 88, 1, 14, 229, 33, 350, 29, 85, 738, 143, 304, 217, 805, 2421, 166, 370, 616, 111, 621, 543, 160, 200, 1825, 909, 256

Offset

1,1

Links

Table of n, a(n) for n=1..63.

Example

2*3*5 - 13 = 17, prime; 2*3*5 + 13 = 43, prime; so for n=3, k=1.

Mathematica

Primorial[n_] := Product[ Prime[i], {i, n}]; f[n_] := Block[{k = 1, p = Primorial[n], q = Prime[n + 3]}, While[k*p - q < 2 || !PrimeQ[k*p - q] || !PrimeQ[k*p + q], k++ ]; k]; Table[ f[n], {n, 63}] (* Robert G. Wilson v, Aug 31 2004 *)

Crossrefs

Sequence in context: A159671 A094853 A096937 * A204063 A132400 A232810

Adjacent sequences: A097524 A097525 A097526 * A097528 A097529 A097530

Keyword

easy,nonn

Author

Pierre CAMI, Aug 27 2004

Extensions

More terms from Robert G. Wilson v, Aug 31 2004

Status

approved