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A375752 a(n) is the difference between T=n*(n+1)/2 and the largest prime not exceeding T. 0
0, 1, 3, 2, 2, 5, 5, 2, 2, 5, 5, 2, 2, 7, 5, 2, 4, 9, 11, 2, 2, 5, 7, 8, 2, 5, 5, 2, 2, 5, 5, 4, 2, 11, 5, 2, 2, 7, 9, 2, 16, 5, 7, 2, 12, 5, 5, 2, 16, 5, 5, 2, 2, 9, 13, 16, 2, 11, 7, 2, 2, 5, 11, 2, 4, 5, 5, 4, 8, 5, 7, 2, 8, 7, 9, 2, 2, 23, 11, 2, 12, 17, 11, 12, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,3
LINKS
Table of n, a(n) for n=2..86.
FORMULA
a(n) = A000217(n) - A065384(n). - Michel Marcus, Aug 27 2024
PROG
(PARI) a(n) = my(t=n*(n+1)/2); t - precprime(t)
(Python)
from sympy import prevprime
def A375752(n): return (t:=n*(n+1)//2) - prevprime(t) # Karl-Heinz Hofmann, Aug 27 2024
CROSSREFS
Cf. A000217, A007917, A065384, A075402, A375753, A375754.
Sequence in context: A282161 A205675 A342331 * A058608 A112196 A021035
Adjacent sequences: A375742 A375743 A375751 * A375753 A375754 A375755
KEYWORD
nonn,easy,new
AUTHOR
Hugo Pfoertner, Aug 26 2024
STATUS
approved

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Last modified August 29 15:03 EDT 2024. Contains 375517 sequences. (Running on oeis4.)