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 A145023 Primes p of the form 4k+1 for which s=5 is the least positive integer such that s*p - floor(sqrt(s*p))^2 is a perfect square. 13
 353, 373, 449, 461, 521, 541, 593, 653, 673, 757, 769, 797, 821, 829, 941, 953, 1009, 1021, 1061, 1069, 1097, 1193, 1217, 1249, 1277, 1361, 1381, 1481, 1489, 1549, 1597, 1613, 1657, 1669, 1693, 1709, 1733, 1777, 1801, 1877, 1889, 1973, 2053, 2069, 2081 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Primes p == 1 (mod 4) such that A245474(p) = 5. These numbers are a subset of {A245440}. Curiosity: a(n) = A245440(n) for all n < 25. - Thomas Ordowski, Jul 22 2014 LINKS EXAMPLE a(1)=353 since p=353 is the least prime of the form 4k+1 for which s*p - (floor(sqrt(s*p)))^2 is not a perfect square for s=1,...,4, but 5*p - (floor(sqrt(5*p)))^2 is a perfect square (for p=353 it is 1). PROG (PARI) s=[]; forprime(p=2, 3000, if(p%4==1 && !issquare(p-sqrtint(p)^2) && !issquare(2*p-sqrtint(2*p)^2) && !issquare(3*p-sqrtint(3*p)^2) && !issquare(4*p-sqrtint(4*p)^2) && issquare(5*p-sqrtint(5*p)^2), s=concat(s, p))); s \\ Colin Barker, Jul 23 2014 CROSSREFS Cf. A002144, A145016, A145022, A245440, A245474. Sequence in context: A156177 A104160 A245440 * A343714 A343715 A177678 Adjacent sequences:  A145020 A145021 A145022 * A145024 A145025 A145026 KEYWORD nonn AUTHOR Vladimir Shevelev, Sep 29 2008 STATUS approved

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Last modified June 14 15:19 EDT 2021. Contains 345025 sequences. (Running on oeis4.)