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A085273 Difference between n-th composite number and its largest prime divisor. 3
2, 3, 6, 6, 5, 9, 7, 10, 14, 15, 15, 14, 11, 21, 20, 13, 24, 21, 25, 30, 22, 17, 28, 33, 19, 26, 35, 35, 33, 40, 23, 45, 42, 45, 34, 39, 51, 44, 49, 38, 29, 55, 31, 56, 62, 52, 55, 51, 46, 63, 69, 37, 70, 57, 66, 65, 75, 78, 41, 77, 68, 43, 58, 77, 85, 78, 69, 62, 47, 76, 93, 91 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
For 91=7*13 we have 91-13 = 78.
For 92=2*2*23 we have 92-23 = 69.
MATHEMATICA
DeleteCases[Table[n - FactorInteger[n][[-1, 1]], {n, 100}], 0 _] (* Ivan Neretin, Jun 20 2019 *)
PROG
(PARI) cminusp2(n) = { for(x=2, n, forstep(p=x, 2, -1, if(isprime(p) & x%p==0 & isprime(x)==0, print1(x-p, ", "); break); ) ) }
CROSSREFS
Sequence in context: A124498 A197334 A113399 * A151850 A290223 A274213
KEYWORD
easy,nonn
AUTHOR
Cino Hilliard, Aug 12 2003
EXTENSIONS
Offset corrected by Ivan Neretin, Jun 20 2019
STATUS
approved

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Last modified February 23 19:35 EST 2024. Contains 370283 sequences. (Running on oeis4.)