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A113638 In the sequence of nonnegative integers subtract 1 from each prime number. 5
0, 1, 1, 2, 4, 4, 6, 6, 8, 9, 10, 10, 12, 12, 14, 15, 16, 16, 18, 18, 20, 21, 22, 22, 24, 25, 26, 27, 28, 28, 30, 30, 32, 33, 34, 35, 36, 36, 38, 39, 40, 40, 42, 42, 44, 45, 46, 46, 48, 49, 50, 51, 52, 52, 54, 55, 56, 57, 58, 58, 60, 60, 62, 63, 64, 65, 66, 66, 68, 69, 70, 70, 72 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
LINKS
FORMULA
a(n) = A014684(n), n>0. - R. J. Mathar, Aug 13 2008
MATHEMATICA
Table[If[PrimeQ[n], n-1, n], {n, 0, 80}] (* Harvey P. Dale, Sep 10 2017 *)
PROG
(Python)
from sympy import isprime
def A113638(n): return n-int(isprime(n)) # Chai Wah Wu, Oct 14 2023
CROSSREFS
Cf. A014684.
Sequence in context: A211390 A363030 A014684 * A187323 A262504 A211514
KEYWORD
easy,nonn
AUTHOR
Cino Hilliard, Jan 15 2006
EXTENSIONS
Name corrected by Wolfdieter Lang, Apr 22 2015
STATUS
approved

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Last modified February 24 02:58 EST 2024. Contains 370288 sequences. (Running on oeis4.)