

A085273


Difference between nth 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
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OFFSET

1,1


LINKS



EXAMPLE

For 91=7*13 we have 9113 = 78.
For 92=2*2*23 we have 9223 = 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(xp, ", "); break); ) ) }


CROSSREFS



KEYWORD

easy,nonn


AUTHOR



EXTENSIONS



STATUS

approved



