A228946 Numbers m such that m^3 - k^3 is a square for some k < m, k > 0.
8, 10, 14, 28, 32, 33, 40, 56, 57, 65, 71, 72, 74, 78, 90, 105, 112, 114, 126, 128, 130, 132, 140, 148, 154, 155, 160, 176, 193, 200, 217, 218, 224, 228, 250, 252, 260, 266, 273, 280, 284, 288, 296, 297, 305, 312, 329, 336, 344, 349, 350, 360, 392
Offset: 1
Keywords
Links
- Nathaniel Johnston, Table of n, a(n) for n = 1..5000
Programs
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Maple
isA228946 := proc (n) local k; for k to n-1 do if issqr(n^3-k^3) then return true end if end do; return false end proc; for n from 1 to 400 do if isA228946(n)then print(n): end if: end do: # Nathaniel Johnston, Oct 07 2013
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Mathematica
k3sQ[n_]:=Count[n^3-Range[n-1]^3,?(IntegerQ[Sqrt[#]]&)]>0; Select[ Range[ 400],k3sQ] (* _Harvey P. Dale, May 07 2017 *)
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PARI
for(n=1,999,for(k=1,n-1, issquare(n^3-k^3) & !print1(n",") & break))
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PARI
is(n)=for(k=1,n-1, issquare(n^3-k^3) & return(1))
Formula
a(n) = A066648(n)^(1/3). - Amiram Eldar, Mar 20 2025
Comments