

A212488


Smallest k>0 such that (5^nk)*5^n1 and (5^nk)*5^n+1 are a twin prime pair or 0 if no such k exists.


2



0, 1, 11, 1, 17, 85, 17, 25, 71, 25, 83, 673, 3623, 1069, 401, 1225, 1361, 409, 3449, 2581, 779, 613, 605, 781, 395, 5797, 17, 6967, 755, 361, 3443, 5467, 6857, 679, 53, 9355, 3287, 2941, 22385, 6091, 8423, 685, 13649, 2437, 113, 19393, 19781, 12253, 53603, 21049, 5321, 2149, 21779
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OFFSET

1,3


COMMENTS

Conjecture: There is always one such k if n>1.


LINKS

Pierre CAMI, Table of n, a(n) for n = 1..501


PROG

(PFGW64 and SCRIPTIFY)
SCRIPT
DIM nn, 1
DIM kk
DIM jj
DIMS tt
OPENFILEOUT myfile, a(n).txt
OPENFILEOUT myf, b(n).txt
LABEL loopn
SET nn, nn+1
SET jj, 0
IF nn>500 THEN END
SET kk, 1
LABEL loopk
SET kk, kk+2
SETS tt, %d, %d\,; nn; kk
PRP (5^nnkk)*5^nn1, tt
IF ISPRP THEN GOTO a
IF ISPRIME THEN GOTO a
GOTO loopk
LABEL a
SET jj, jj+1
PRP (5^nnkk)*5^nn+1, tt
IF ISPRP THEN GOTO d
IF ISPRIME THEN GOTO d
GOTO loopk
LABEL d
WRITE myfile, tt
SETS tt, %d, %d\,; nn; jj
WRITE myf, tt
GOTO loopn


CROSSREFS

Cf. A212487
Sequence in context: A280506 A222803 A201132 * A178243 A040131 A282868
Adjacent sequences: A212485 A212486 A212487 * A212489 A212490 A212491


KEYWORD

nonn


AUTHOR

Pierre CAMI, Jul 18 2012


STATUS

approved



