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A373792
a(n) = A373390(k-1) - A373390(k), where k is the index of prime(n) in A373390.
2
-1, -1, 9, -1, 28, -2, 21, -2, 52, 33, -2, 80, 39, 45, 51, 112, 63, -2, 69, 136, 144, 152, 170, 176, 99, 196, 202, 216, 212, 216, 248, 254, 270, 272, 296, 296, 159, 320, 328, 340, 352, 354, 364, 368, 376, 384, 410, 428, 442, 446, 454, 466, 470, 484, 496, 504, 516, 518, 524, 538, 542, 562
OFFSET
1,3
COMMENTS
This is the difference between the term immediately preceding prime(n) in A373390 and prime(n).
The first 37 terms are somewhat irregular. See A373793 for the behavior beyond that point.
LINKS
EXAMPLE
For n = 3, prime(3) = 5, A373390(9) = 5, A373390(8) = 14, so a(3) = 14 - 5 = 9.
MATHEMATICA
With[{s = Import["https://oeis.org/A373390/b373390.txt", "Data"][[All, -1]]}, MapIndexed[s[[#1 - 1]] - Prime@ First[#2] &, Values[KeySort@ KeySelect[PositionIndex[s], PrimeQ] ][[All, 1]] ] ] (* Michael De Vlieger, Jun 29 2024 *)
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Jun 29 2024
STATUS
approved