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A071256 Smallest multiple of n sandwiched between twin primes. 6
4, 4, 6, 4, 30, 6, 42, 72, 18, 30, 198, 12, 312, 42, 30, 192, 102, 18, 228, 60, 42, 198, 138, 72, 150, 312, 108, 420, 348, 30, 1302, 192, 198, 102, 420, 72, 1998, 228, 312, 240, 1230, 42, 1032, 660, 180, 138, 282, 192, 882, 150, 102, 312, 6360, 108, 660 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Conjecture: lim sup n ->infinity a(n)/n^2 exists = C, where 0<C<1. - Benoit Cloitre, May 23 2002

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

MATHEMATICA

Table[ s = 2; While[ Mod[s, n] + 2 - Boole[ PrimeQ[s - 1]] - Boole[ PrimeQ[s + 1]] > 0, s++]; s, {n, 1, 55}] (* Jean-Fran├žois Alcover, Dec 08 2011, after Pari *)

With[{tpm=Mean/@Select[Partition[Prime[Range[1000]], 2, 1], #[[2]]-#[[1]] == 2&]}, Flatten[Table[Select[tpm, Divisible[#, n]&, 1], {n, 60}]]] (* Harvey P. Dale, Apr 12 2012 *)

PROG

(PARI) for(n=1, 100, s=2; while(s%n+2-isprime(s-1)-isprime(s+1)>0, s++); print1(s, ", "))

CROSSREFS

Cf. A071558

Sequence in context: A339719 A276683 A247343 * A078240 A296844 A332917

Adjacent sequences:  A071253 A071254 A071255 * A071257 A071258 A071259

KEYWORD

nice,nonn

AUTHOR

Amarnath Murthy, May 22 2002

EXTENSIONS

More terms from Benoit Cloitre, May 23 2002

STATUS

approved

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Last modified June 20 02:17 EDT 2021. Contains 345154 sequences. (Running on oeis4.)