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A163248 Sum of the n-th composite number plus the number of composite numbers less than the n-th noncomposite number. 1
4, 6, 8, 10, 12, 17, 20, 24, 26, 31, 38, 40, 46, 51, 53, 57, 63, 69, 72, 79, 83, 85, 91, 95, 102, 110, 114, 117, 122, 124, 128, 143, 147, 153, 155, 165, 168, 174, 180, 184, 190, 197, 200, 210, 212, 216, 218, 231, 243, 247 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Bo Gyu Jeong, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A002808(n) + A162177(n) = A008578(n) + A073169(n).

MAPLE

nnc:= 1: nc:= 0; b[nnc]:= 0:b[0]:= 0:

for x from 2 to 1000 do

   if isprime(x) then

     nnc:= nnc+1; b[nnc]:= b[nnc-1];

   else

     b[nnc]:= b[nnc]+1;

     nc:= nc+1;

     c[nc]:= x;

   fi

od:

seq(b[n-1]+c[n], n=1..min(nnc, nc)); # Robert Israel, Jan 09 2015

CROSSREFS

Sequence in context: A076298 A194579 A194594 * A034288 A131984 A307542

Adjacent sequences:  A163245 A163246 A163247 * A163249 A163250 A163251

KEYWORD

nonn,easy,less

AUTHOR

Jaroslav Krizek, Jul 23 2009

EXTENSIONS

Corrected for Aug 2009 change of offset in A158611 and A008578 by Jaroslav Krizek, Jan 27 2010

STATUS

approved

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Last modified May 25 22:17 EDT 2019. Contains 323576 sequences. (Running on oeis4.)