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A236569 Least term p of A236568 with 2*n - p prime, or 0 if such a prime p does not exist. 2
0, 0, 3, 3, 3, 5, 3, 3, 5, 3, 3, 5, 3, 5, 11, 3, 3, 5, 31, 3, 5, 3, 3, 5, 3, 5, 11, 3, 5, 31, 3, 3, 5, 31, 3, 5, 3, 3, 5, 43, 3, 5, 3, 5, 11, 3, 5, 43, 31, 3, 5, 3, 3, 5, 3, 3, 5, 3, 5, 11, 43, 11, 43, 31, 3, 5, 3, 5, 11, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

The conjecture in A236566 implies that a(n) > 0 for all n > 2.

LINKS

Zhi-Wei Sun, Table of n, a(n) for n = 1..10000

EXAMPLE

a(3) = 3 since prime(3 + 2) + 2 = 11 + 2 = 13 and 2*3 - 3 = 3 are both prime, but prime(2 + 2) + 2 = 9 is not.

MATHEMATICA

p[m_]:=PrimeQ[Prime[m+2]+2]

Do[Do[If[p[Prime[k]]&&PrimeQ[2n-Prime[k]], Print[n, " ", Prime[k]]; Goto[aa]], {k, 1, PrimePi[2n-1]}];

Print[n, " ", 0]; Label[aa]; Continue, {n, 1, 100}]

CROSSREFS

Cf. A000040, A020481, A236566, A236568.

Sequence in context: A302387 A049613 A002373 * A103153 A162022 A318240

Adjacent sequences:  A236566 A236567 A236568 * A236570 A236571 A236572

KEYWORD

nonn

AUTHOR

Zhi-Wei Sun, Jan 29 2014

STATUS

approved

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Last modified August 6 18:20 EDT 2020. Contains 336256 sequences. (Running on oeis4.)