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 A217833 The largest number not exceeding n^2, such that there are no terms of the sequence in the interval (a(n-1)/2, a(n)/2), with a(0)=0, a(1)=1. 3
 0, 1, 2, 4, 8, 16, 32, 49, 64, 81, 98, 121, 128, 162, 196, 225, 242, 256, 324, 361, 392, 441, 450, 484, 512, 625, 648, 722, 784, 841, 882, 900, 968, 1024, 1156, 1225, 1250, 1296, 1444, 1521, 1568, 1681, 1682, 1764, 1800, 1936, 2048, 2209, 2304, 2312, 2450 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Every term has the form s*2^k, where s>=0 is a square and k>=0. LINKS Alois P. Heinz, Table of n, a(n) for n = 0..1000 FORMULA a(n) = min(2*a(k+1), n^2) for n>=2 and a(k) <= a(n-1)/2 < a(k+1). EXAMPLE Let us find a(6), knowing the previous terms. Since a(5) = 16 and a(4)<=16/2i do if a(k)<=t then i:=k else j:=k fi;                        k:= iquo(i+j, 2) od;          min(n^2, 2*a(k+1))       fi     end: seq (a(n), n=0..100);  # Alois P. Heinz, Nov 03 2012 CROSSREFS Cf. A217689. Sequence in context: A323395 A326079 A222193 * A226930 A326751 A297702 Adjacent sequences:  A217830 A217831 A217832 * A217834 A217835 A217836 KEYWORD nonn AUTHOR Vladimir Shevelev, Oct 12 2012 EXTENSIONS More terms from Alois P. Heinz, Nov 02 2012 STATUS approved

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Last modified September 18 20:05 EDT 2020. Contains 337173 sequences. (Running on oeis4.)