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 A240475 Primes that are midway between the closest flanking squarefree numbers. 6
 2, 17, 19, 53, 89, 163, 197, 199, 233, 251, 269, 271, 293, 307, 337, 379, 449, 487, 491, 521, 557, 593, 631, 701, 739, 751, 809, 811, 881, 883, 919, 953, 991, 1013, 1049, 1061, 1063, 1097, 1151, 1171, 1279, 1459, 1471, 1493, 1531, 1549, 1567, 1601, 1637 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Primes for which the corresponding A240473(m) is equal to A240474(m). Primes equal to the average of the closest flanking squarefree numbers. Primes equal to the average of three consecutive squarefree numbers. Most terms are such that a(n)+2 and a(n)-2 are the closest squarefree numbers. The first term > 2 for which this is not the case is a(880) = 47527. 494501773, 765921647, 930996623 are the terms < 10^9 that also belong to A176141. LINKS Chris Boyd, Table of n, a(n) for n = 1..10000 EXAMPLE 19 is a term because it is midway between the closest flanking squarefree numbers 17 and 21. On the other hand, 29 is not a term because it is not midway between the closest flanking squarefree numbers 26 and 30. PROG (PARI) forprime(p=1, 1650, forstep(j=p-1, 1, -1, if(issquarefree(j), L=j; break)); for(j=p+1, 2*p, if(issquarefree(j), G=j; break)); if(G-p==p-L, print1(p", "))) CROSSREFS Cf. A000040, A075430, A075432, A166003, A176141, A240473, A240474, A240476. Sequence in context: A042925 A019413 A040138 * A107139 A042055 A075683 Adjacent sequences:  A240472 A240473 A240474 * A240476 A240477 A240478 KEYWORD nonn AUTHOR Chris Boyd, Apr 06 2014 STATUS approved

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Last modified October 20 21:29 EDT 2019. Contains 328273 sequences. (Running on oeis4.)