A209063 Let p = A099180(n) be the n-th prime which is greater than its reversal p'; a(n) = number of ways to write p as a multiple of p' +- q where q is a prime < p.
1, 2, 0, 1, 4, 3, 0, 2, 1, 1, 1, 1, 1, 1, 0, 0, 3, 2, 4, 0, 0, 2, 0, 2, 1, 3, 1, 1, 1, 1, 1, 4, 1, 4, 2, 0, 1, 2, 1, 1, 1, 2, 1, 0, 1, 1, 1, 4, 4, 1, 0, 1, 1, 2, 0, 3, 2, 0, 0, 3, 1, 3, 0, 0, 1, 3, 0, 0, 2, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1
Offset: 1
Examples
For n=6, p = 71, p' = 17 and there are three solutions: 71 = 2*17 + 3771 = 4*17 + 371 = 6*17 - 31, so a(6) = 3.
Programs
-
PARI
A209063(n)=A209914(A099180(n)) \\ M. F. Hasler, Mar 15 2012
Comments