A360840 3-full numbers (A036966) sandwiched between twin primes.
432, 2592, 139968, 444528, 472392, 995328, 3456000, 5174928, 6561000, 10125000, 15552000, 15804072, 17496000, 25299648, 28449792, 37340352, 54675000, 63700992, 85957848, 88723728, 99574272, 120891312, 144027072, 169869312, 177147000, 197413632, 253125000, 259308000
Offset: 1
Keywords
Examples
432 = 2^4 * 3^3 is a term since it is 3-full and 431 and 433 are twin primes.
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
- Eric Weisstein's World of Mathematics, Twin Primes.
- Wikipedia, Powerful number: Generalization.
- Index entries for sequences related to powerful numbers.
Programs
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Mathematica
Select[6*Range[10^6], PrimeQ[# - 1] && PrimeQ[# + 1] && Min[FactorInteger[#][[;; , 2]]] > 2 &]
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PARI
is(n) = isprime(n-1) && isprime(n+1) && vecmin(factor(n)[,2]) > 2;