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 A080793 Starting with a(0) = 1, smallest number k > a(n-1) such that, for all a(m) with m < n, k + a(m) is not squarefree. 4
 1, 3, 15, 17, 147, 233, 577, 735, 3615, 4335, 8117, 9505, 10947, 14403, 25215, 30833, 128773, 220647, 251173, 522003, 617547, 770977, 926117, 967335, 1455533, 1662533, 1960215, 2389517, 2469747, 3528147, 4674747, 5556747, 5730135, 5859903, 10892847, 12127647, 15170547 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Amiram Eldar, Table of n, a(n) for n = 0..10000 C. B. Lacampagne, C. A. Nicol, and J. L. Selfridge, Sets With Non-Squarefree Sums, in: Richard Mollin (ed.), Number Theory: Proceedings of the First Conference of the Canadian Number Theory Association, Held at the Banff Center, Banff, Alberta, April 17-27, 1988, Berlin; New York: W. de Gruyter, 1990, pp. 299-310. MATHEMATICA a[0] = 1; a[n_] := a[n] = Module[{t = Array[a, n, 0], k = a[n - 1] + 1}, While[AnyTrue[t, SquareFreeQ[k + #] &], k++]; k]; Array[a, 20, 0] (* Amiram Eldar, Aug 21 2023 *) PROG (PARI) v=vector(60); v[1]=1; print1("1, "); for(n=2, 60, for(k=v[n-1]+1, 10^15, 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, A077225, A085902. Sequence in context: A080705 A032921 A163785 * A077225 A236526 A039559 Adjacent sequences: A080790 A080791 A080792 * A080794 A080795 A080796 KEYWORD nonn AUTHOR Ralf Stephan, Mar 25 2003 EXTENSIONS More terms from Lambert Klasen (Lambert.Klasen(AT)gmx.net) and lambert.herrgesell(AT)aschendorff.de, Jul 26 2005 a(33)-a(36) from Amiram Eldar, Aug 21 2023 STATUS approved

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Last modified September 25 13:12 EDT 2023. Contains 365647 sequences. (Running on oeis4.)