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A209915
Number of ways the n-th prime p(n) can be written as a multiple of its reversal A004086(p) +/- a prime q < p(n).
1
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 2, 0, 0, 1, 0, 4, 0, 3, 0, 0, 2, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 2, 4, 0, 0, 0, 0, 0, 2
OFFSET
1,13
COMMENTS
Sequence A209063 is a subsequence which contains all (but not only) nonzero terms.
FORMULA
PROG
(PARI) a(n)={my(r=A004086(n=prime(n))); sum(k=1, (2*n-1)\r, isprime(abs(n-k*r)))}
CROSSREFS
Cf. A209063.
Sequence in context: A323911 A322581 A347083 * A349386 A355687 A349349
KEYWORD
nonn,base
AUTHOR
M. F. Hasler, Mar 15 2012
STATUS
approved