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A226176
Refactorable numbers between a pair of twin primes.
1
12, 18, 60, 72, 108, 180, 228, 240, 348, 600, 828, 882, 1152, 1620, 1668, 1788, 2088, 2340, 2688, 3120, 3168, 3252, 3360, 3372, 3528, 3852, 4050, 4128, 4548, 4788, 4932, 5280, 5520, 5652, 5868, 6660, 6828, 6948, 6960, 7212, 7308, 8292, 8388, 8628, 9012
OFFSET
1,1
COMMENTS
Refactorable numbers that are the averages of twin pairs.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Range[10000], PrimeQ[# - 1] && PrimeQ[# + 1] && Mod[#, DivisorSigma[0, #]] == 0 &] (* T. D. Noe, Jun 03 2013 *)
PROG
(PARI) p=2; forprime(q=3, 1e4, if(q-p==2 && (p+1)%numdiv(p+1)==0, print1(p+1", ")); p=q) \\ Charles R Greathouse IV, Mar 18 2014
CROSSREFS
Sequence in context: A279369 A119147 A370395 * A177426 A232384 A086301
KEYWORD
nonn
AUTHOR
Irina Gerasimova, May 29 2013
STATUS
approved