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 A132295 Sum of the nonsquare numbers not larger than n. 0
 0, 2, 5, 5, 10, 16, 23, 31, 31, 41, 52, 64, 77, 91, 106, 106, 123, 141, 160, 180, 201, 223, 246, 270, 270, 296, 323, 351, 380, 410, 441, 473, 506, 540, 575, 575, 612, 650, 689, 729, 770, 812, 855, 899, 944, 990, 1037, 1085, 1085, 1135, 1186, 1238, 1291, 1345 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA Let r = floor(sqrt(n)). Then a(n) = n(n+1)/2 - r(r+1)(2r+1)/6. EXAMPLE Let n=5. The sum of the nonsquare numbers <= 5 is 2+3+5 = 10, the 5th entry in the sequence. PROG (PARI) sumNsq(n)= { for(x=1, n, r=floor(sqrt(x)); sq=r*(r+1)*(2*r+1)/6; sn=x*(x+1)/2; print1(sn-sq", ")) } CROSSREFS Cf. A000037, A086849. Sequence in context: A081240 A184443 A238655 * A086651 A074495 A081467 Adjacent sequences:  A132292 A132293 A132294 * A132296 A132297 A132298 KEYWORD nonn AUTHOR Cino Hilliard, Nov 07 2007 EXTENSIONS Definition corrected. - R. J. Mathar, Sep 10 2016 STATUS approved

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Last modified September 29 04:42 EDT 2020. Contains 337420 sequences. (Running on oeis4.)