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A264719
Numbers that are greater than the average of their closest flanking primes.
4
10, 11, 16, 17, 22, 27, 28, 29, 35, 36, 37, 40, 41, 46, 51, 52, 57, 58, 59, 65, 66, 67, 70, 71, 77, 78, 79, 82, 87, 88, 94, 95, 96, 97, 100, 101, 106, 107, 112, 121, 122, 123, 124, 125, 126, 127, 130, 135, 136, 137, 145, 146, 147, 148, 149, 155, 156, 161, 162
OFFSET
1,1
COMMENTS
Numbers that are nearer to the immediately next prime than to the immediately previous prime.
This sequence may be viewed as a generalization of A051634 (the strong primes) that includes qualifying composite numbers.
The union of this sequence with A264720 & A145025 is A000027 (omitting 1 & 2).
EXAMPLE
a(11) = 37 because 37 > (31 + 41)/2 = 36.
a(12) = 40 because 40 > (37 + 41)/2 = 37.
MATHEMATICA
Select[Range@ 162, # > (Abs@ NextPrime[#, -1] + NextPrime@ #)/2 &] (* Michael De Vlieger, Nov 22 2015 *)
PROG
(PARI) test(n)= {if(n-precprime(n-1)>nextprime(n+1)-n&&n>2, return(1), return(0))}
for(i=1, 200, if(test(i), print1(i, ", ")))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Chris Boyd, Nov 21 2015
STATUS
approved