|
Search: id:A065022
|
|
|
| A065022 |
|
The sums of the composite numbers up to n-1 and n+1 are twin primes. |
|
+0
1
|
|
| 4, 8, 290, 340, 352, 412, 489, 610, 774, 785, 1227, 1295, 1306, 1795, 1853, 1918, 1945, 2014, 2266, 2502, 2885, 3063, 3133, 3178, 3265, 3482, 3486, 3680, 3760, 3843, 3973, 3995, 4124, 4794, 5677, 5769, 5965, 6123, 7555, 7653, 7696, 7765, 7786, 8023
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
EXAMPLE
|
4+6+8 = 18 and 18 +/-1 are twin primes.
|
|
MATHEMATICA
|
Composite[n_Integer] := (k = n + PrimePi[n] + 1; While[k - PrimePi[k] - 1 != n, k++ ]; k); s = 0; Do[m = Composite[n]; s = s + m; If[ PrimeQ[s - 1] && PrimeQ[s + 1], Print[m]], {n, 1, 10^4} ]
|
|
CROSSREFS
|
Sequence in context: A085631 A074073 A090653 this_sequence A012994 A136386 A013443
Adjacent sequences: A065019 A065020 A065021 this_sequence A065023 A065024 A065025
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 01 2001
|
|
|
Search completed in 0.002 seconds
|
