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A309123 a(1) = 50 and for any n > 0, a(n+1)^2 is the smallest square that begins with a(n). 2

%I

%S 50,71,267,517,2274,1508,3884,1971,444,667,817,286,535,732,856,2926,

%T 541,736,858,293,542,233,483,695,834,2888,16995,41225,20304,4506,6713,

%U 2591,5091,22564,47502,21795,46686,21607,46484,215602,46433,68142,261041,510922

%N a(1) = 50 and for any n > 0, a(n+1)^2 is the smallest square that begins with a(n).

%C This sequence is similar to A308055.

%C The initial value (50) seems to be the first one for which the iteration of A018796 diverges; there are neither duplicates nor squares among the first 79000 terms.

%H Rémy Sigrist, <a href="/A309123/b309123.txt">Table of n, a(n) for n = 1..1000</a>

%H Rémy Sigrist, <a href="/A309123/a309123.gp.txt">PARI program for A309123</a>

%F a(1) = 50 and then a(n+1) = A018796(a(n)) for n > 0.

%e The first terms, alongside the square of a(n+1), are:

%e n a(n) a(n+1)^2

%e -- ---- --------

%e 1 50 5041

%e 2 71 71289

%e 3 267 267289

%e 4 517 5171076

%e 5 2274 2274064

%e 6 1508 15085456

%e 7 3884 3884841

%e 8 1971 197136

%e 9 444 444889

%e 10 667 667489

%e 11 817 81796

%e 12 286 286225

%e 13 535 535824

%e 14 732 732736

%e 15 856 8561476

%e 16 2926 292681

%o (PARI) See Links section.

%Y Cf. A018796, A308055.

%K nonn,base

%O 1,1

%A _Rémy Sigrist_, Jul 13 2019

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Last modified January 20 17:31 EST 2022. Contains 350472 sequences. (Running on oeis4.)