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 A077225 Starting with a(0) = 1, smallest squarefree number k such that, for all a(m), m < n, k + a(m) is not squarefree. 5
 1, 3, 15, 17, 233, 291, 577, 723, 1455, 3615, 8117, 8835, 9505, 30833, 128773, 130827, 239595, 273435, 426891, 654135, 676297, 926117, 1455533, 1662533, 2389517, 2762427, 2820927, 7994449, 8098527, 14319073, 16766835, 20506733, 27606617, 31627817, 43558023, 55566015 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Table of n, a(n) for n=0..35. EXAMPLE 17 belongs to this sequence as 17 + 1, 17 + 3, 17 + 15 all are divisible by some square. MATHEMATICA a = 1; a[n_] := a[n] = Module[{t = Array[a, n, 0], k = a[n - 1] + 1}, While[! SquareFreeQ[k] || AnyTrue[t, SquareFreeQ[k + #] &], k++]; k]; Array[a, 20, 0] (* Amiram Eldar, Aug 21 2023 *) PROG (PARI) v=vector(60); v=1; print1("1, "); for(n=2, 60, for(k=1, 10^15, if(issquarefree(k), s=0; for(l=1, n-1, if(issquarefree(k+v[l]), break); s=s+1)); if(s==n-1, print1(k", "); v[n]=k; break))) CROSSREFS Cf. A013929, A077224, A080793, A085902. Sequence in context: A032921 A163785 A080793 * A236526 A039559 A045753 Adjacent sequences: A077222 A077223 A077224 * A077226 A077227 A077228 KEYWORD nonn AUTHOR Amarnath Murthy, Nov 03 2002 EXTENSIONS Edited by Ralf Stephan, Mar 25 2003 More terms from Sam Alexander, Dec 12 2003 a(22) corrected and a(33)-a(35) added by Amiram Eldar, Aug 21 2023 STATUS approved

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Last modified September 21 02:47 EDT 2023. Contains 365486 sequences. (Running on oeis4.)