A336299 (Least prime > prime(n)/2) - (greatest prime < prime(n)/2).
1, 2, 2, 2, 4, 4, 2, 4, 4, 2, 4, 4, 6, 6, 2, 2, 6, 6, 6, 4, 2, 4, 6, 6, 6, 6, 6, 6, 6, 6, 4, 4, 6, 6, 6, 4, 6, 6, 8, 8, 8, 8, 4, 4, 4, 4, 14, 14, 14, 14, 14, 14, 4, 6, 6, 6, 2, 10, 10, 10, 6, 6, 6, 6, 4, 6, 6, 6, 6, 2, 10, 10, 10, 2, 4, 2, 12, 12, 12, 12, 12
Offset: 3
Keywords
Examples
Prime(3)/2 = 2.5, so that a(3) = 3 - 2 = 1. Prime(4)/2 = 3.5, so that a(4) = 5 - 3 = 2.
Programs
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Mathematica
z = 120; t = Table[NextPrime[Prime[n]/2], {n, 3, z}]; (* cf. A039734, A079953 *) u = NextPrime[t, -1] (* A336298 *) t - u (* A336299 *) -
PARI
a(n) = my(x=prime(n)/2); nextprime(x) - precprime(x); \\ Michel Marcus, Nov 18 2020