1,13

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

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

A209915 = A209914 o A000040.

(PARI) a(n)={my(r=A004086(n=prime(n))); sum(k=1, (2*n-1)\r, isprime(abs(n-k*r)))}

Cf. A209063.

Sequence in context: A323911 A322581 A347083 * A349386 A349349 A349443

Adjacent sequences: A209912 A209913 A209914 * A209916 A209917 A209918

nonn,base

M. F. Hasler, Mar 15 2012

approved