A287609 Intersection of A034961 and A127345.
31, 71, 311, 551, 1151, 14831, 45791, 455471, 2035271, 6345239, 7241615, 8290031, 8329991, 9086231, 9324351, 10449575, 11497199, 15454151, 16515815, 18337271, 20650811, 22946591, 27609311, 33220079, 40487471, 44106191, 45015791, 49021199, 53315519, 54536519
Offset: 1
Keywords
Examples
31 is in the sequence because it is both the total of three consecutive primes (7 + 11 + 13) and it is (2*3 + 2*5 + 3*5) = (6 + 10 + 15). - _Michael De Vlieger_, May 28 2017
Links
- Chai Wah Wu, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
Intersection[Map[Total, #], Map[#1 #2 + #1 #3 + #2 #3 & @@ # &, #]] &@ Partition[Prime@ Range[10^6], 3, 1] (* Michael De Vlieger, May 28 2017 *)
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Python
from _future_ import division from sympy import isprime, prevprime, nextprime A287609_list, p, q, r = [], 2, 3, 5 while r < 10**6: n = p*(q+r) + q*r m = n//3 pm, nm = prevprime(m), nextprime(m) k = n - pm - nm if isprime(m): if m == k: A287609_list.append(n) else: if nextprime(nm) == k or prevprime(pm) == k: A287609_list.append(n) p, q, r = q, r, nextprime(r) # Chai Wah Wu, May 31 2017
Extensions
More terms from Michael De Vlieger, May 28 2017
Comments