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 A298825 Row sums of A298824. 7
 1, 0, 0, 4, 0, 0, 0, 16, -9, 0, 0, 0, 0, 0, 0, 48, 0, 0, 0, 0, 0, 0, 0, 0, -25, 0, -54, 0, 0, 0, 0, 128, 0, 0, 0, -36, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -49, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 320, 0, 0, 0, 0, 0, 0, 0, -144, 0, 0, 0, 0, 0, 0, 0, 0, -243, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Positions of nonzero entries appear to be given by A001694. LINKS Antti Karttunen, Table of n, a(n) for n = 1..2500 FORMULA From Mats Granvik, Mar 03 2019: (Start) a(n) = n*Sum_{j=1..n} [j divides n]*A000005(n/j)*A306653(j). a(n) = n*Sum_{j=1..n} [j divides n]*A000005(n/j)*Sum_{m=1..n} Sum_{k=1..n} [k divides j]*[j/k divides m]*A008683(j/k)*j/k*[k divides m + 2^p]*A008683(k)*k, p=1,2,3,4,5,...,infinity. (End) MATHEMATICA a[n_] := n*Sum[If[Mod[n, j] == 0, DivisorSigma[0, n/j]*1/j*Sum[Sum[If[Mod[j, k] == 0, If[Mod[m, j/k] == 0, MoebiusMu[j/k]*j/k, 0], 0]*If[Mod[m + 2, k/1] == 0, MoebiusMu[k/1]*k/1, 0], {k, 1, j}], {m, 1, j}], 0], {j, 1, n}]; a /@ Range[85] (* Mats Granvik, Mar 03 2019 *) PROG (PARI) up_to = 256; DirConv(ma, h) = { my(u = matsize(ma)[1], md = matrix(u, u)); for(n=1, u-h, for(k=1, u, md[n, k] = sumdiv(k, d, ma[n, d]*ma[n+h, k/d]))); (md); }; A298825list(up_to) = { my(h=2, matA = matrix(up_to+h, up_to+h, n, k, !(n%k)), matB = matrix(up_to+h, up_to+h, n, k, (!(k%n))*moebius(n)*n), matT = matA*matB, matD = DirConv(matT, 2)); vector(up_to, i, sum(j=1, i, matD[j, i])); }; v298825 = A298825list(up_to); A298825(n) = v298825[n]; \\ Antti Karttunen, Sep 30 2018 CROSSREFS Cf. A298674, A298824, A298826. Sequence in context: A162296 A169773 A236380 * A265831 A264769 A169765 Adjacent sequences:  A298822 A298823 A298824 * A298826 A298827 A298828 KEYWORD sign AUTHOR Mats Granvik, Jan 27 2018 STATUS approved

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Last modified June 13 20:01 EDT 2021. Contains 345009 sequences. (Running on oeis4.)