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A161669
Sum_{j=k(n)..prime(n)} j where k is the n-th nonprime nonnegative integer.
1
3, 6, 9, 13, 38, 55, 108, 124, 185, 330, 376, 550, 671, 736, 897, 1155, 1470, 1566, 1927, 2178, 2266, 2664, 2958, 3444, 4158, 4521, 4653, 5037, 5215, 5580, 7182, 7656, 8418, 8602, 9999, 10251, 11128, 12040, 12597, 13566, 14570, 14875, 16683, 16951, 17612
OFFSET
1,1
EXAMPLE
n k(n) prime(n) Sum_{j=k(n)..prime(n)} j
= ==== ======== ========================
1 0 2 0 + 1 + 2 = 3 = a(1)
2 1 3 1 + 2 + 3 = 6 = a(2)
3 4 5 4 + 5 = 9 = a(3)
4 6 7 6 + 7 = 13 = a(4)
5 8 11 8 + 9 + 10 + 11 = 38 = a(5)
PROG
(PARI) k=0; p=2; for(i=1, 1e2, s=p*(p+1)/2-k*(k-1)/2; print1(s", "); p=nextprime(p+1); while(isprime(k++), ))
CROSSREFS
Sequence in context: A316531 A242339 A086838 * A128261 A310162 A310163
KEYWORD
nonn,base,easy
AUTHOR
Juri-Stepan Gerasimov, Jun 16 2009, Jun 27 2009
EXTENSIONS
Corrected and extended by Charles R Greathouse IV, Mar 25 2010
Name clarified and Example section edited by Jon E. Schoenfield, Feb 10 2019
STATUS
approved