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A305673
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Indices i where a run of zeros starts in A305671.
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5
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2, 15, 55, 108, 195, 256, 370, 419, 437, 782, 1616, 1857, 3055, 4806, 5851, 6142, 6275, 6487, 7161, 7278, 7591, 13041, 13122, 13179, 14904, 14979, 15451, 21767, 32056, 39478, 79649, 148518, 174716, 273952, 400581
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OFFSET
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1,1
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COMMENTS
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LINKS
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MATHEMATICA
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Block[{c = Select[Range[10^3], CompositeQ], s}, s = DivisorSigma[1, c]; Select[SplitBy[Partition[Position[Array[If[Length@ # == 1, #[[1, 1]], 0] &@ Last@ SplitBy[SortBy[Tally@ Take[s, #], Last], Last] &, Length@ s], 0][[All, 1]], 2, 1], Differences], Length@ # > 1 &][[All, 1, 1]]] (* Michael De Vlieger, Jun 14 2018 *)
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PROG
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(PARI) mcv(v) = my(w=vecsort(v, , 8), count=vector(#w), ind=0, i=0); for(x=1, #w, for(y=1, #v, if(w[x]==v[y], count[x]++))); for(k=1, #count, if(count[k]==vecmax(count), ind=k; i++)); if(i > 1, return(0), return(w[ind]))
my(v=[], i=1, t=0); forcomposite(c=1, , v=concat(v, [sigma(c)]); if(mcv(v)==0, if(t==0, print1(i, ", ")); t++, t=0); i++)
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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