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%I #7 Mar 28 2015 22:10:57
%S 1,2,4,8,16,21,24,248,481,681,6212,16212,42421,242484,842484,8168168,
%T 48168162,121621216,816212162,1242421242,4212162124,24212424848,
%U 42484842421,242484842484,816816848168,1684842484816,8168481681621
%N Slowest increasing sequence beginning with 1 whose digits satisfy the rule d*2.
%C Same digits as A061581.
%F d*2, beginning with 1.
%e Read a(5)=16, which produces first digit of a(6)=2 because 1*2=2 and second digit of a(6)=1 and first digit of a(7)=2 because 6*2=12.
%t t = Flatten[ NestList[ Function[x, Flatten[ IntegerDigits[2IntegerDigits[ x]]]], 1, 17]]; a = 0; l = {}; Do[k = 1; While[fd = FromDigits[ Take[t, k]]; a >= fd, k++ ]; t = Drop[t, k]; AppendTo[l, fd]; a = fd, {n, 27}]; l (* _Robert G. Wilson v_, Feb 21 2005 *)
%Y Cf. A061581.
%K base,easy,nonn
%O 1,2
%A _Alexandre Wajnberg_ and _Eric Angelini_, Feb 18 2005
%E More terms from _Robert G. Wilson v_, Feb 21 2005
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