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 A235578 Squareful numbers with squareful neighbors. 4
 49, 99, 125, 243, 244, 343, 351, 424, 476, 549, 604, 725, 775, 845, 846, 847, 1025, 1251, 1275, 1324, 1376, 1421, 1449, 1520, 1665, 1675, 1681, 1682, 1683, 1849, 1863, 1925, 2008, 2024, 2057, 2107, 2151, 2224, 2276, 2349, 2367, 2524, 2528, 2575, 2645, 2825 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A070258(n) + 1. - Amiram Eldar, Feb 09 2021 EXAMPLE 243 is in the sequence because 242 = 2 * 11^2, 243 = 3^5, 244 = 2^2 * 61. 244 is also in the sequence because 245 = 5 * 7^2. But 245 is not in the sequence because 246 = 2 * 3 * 41. MATHEMATICA Select[Range@3051, And @@ Not /@ SquareFreeQ /@ {#-1, #, #+1} &] (* Giovanni Resta, Jan 12 2014 *) Select[Range[2000], Union[MoebiusMu[{# - 1, #, # + 1}]] == {0} &] (* Alonso del Arte, Jan 12 2014 *) PROG (PARI) isok(n) = !issquarefree(n) && !issquarefree(n-1) && !issquarefree(n+1); \\ Michel Marcus, Jan 12 2014 CROSSREFS Subsequence of A013929. Cf. A001694, A070258, A228649 (squarefree numbers with squarefree neighbors). Sequence in context: A031484 A260009 A114013 * A161689 A354342 A230653 Adjacent sequences: A235575 A235576 A235577 * A235579 A235580 A235581 KEYWORD nonn AUTHOR Juri-Stepan Gerasimov, Jan 12 2014 EXTENSIONS Terms corrected by Michel Marcus, Jan 12 2014 STATUS approved

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Last modified February 25 19:44 EST 2024. Contains 370332 sequences. (Running on oeis4.)