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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,13

COMMENTS

Sequence A209063 is a subsequence which contains all (but not only) nonzero terms.

LINKS

Table of n, a(n) for n=1..89.

FORMULA

A209915 = A209914 o A000040.

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 A349349 A349443

Adjacent sequences:  A209912 A209913 A209914 * A209916 A209917 A209918

KEYWORD

nonn,base

AUTHOR

M. F. Hasler, Mar 15 2012

STATUS

approved

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Last modified May 23 23:07 EDT 2022. Contains 353993 sequences. (Running on oeis4.)