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Least number which reaches n under the operation introduced in A100787: first differences are the digits of the sequence.
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%I #11 Jan 02 2023 12:30:48

%S 1,1,3,1,5,3,7,1,9,5,5,3,3,5,3,1,1,5,3,3,11,5,1,1,3,3,5,5,19,13,1,3,1,

%T 5,7,1,7,1,7,5,5,1,13,3,1,1,11,9,1,5,3,1,3,11,1,9,20,13,3,7,1,3,5,1,5,

%U 9,3,5,9,3,11,1,7,3,11,1,5,1

%N Least number which reaches n under the operation introduced in A100787: first differences are the digits of the sequence.

%C E. Angelini proposes to call Wilsonize(n) the sequence starting with n and having as first differences the digits of the (concatenated) terms of the sequence. Then this sequence lists the smallest starting value a(n)=k such that n is a term of Wilsonize(k).

%H E. Angelini, <a href="http://list.seqfan.eu/oldermail/seqfan/2013-February/010751.html">Smallest hitters</a>, SeqFan list, Feb 04 2013

%o (PARI) A211206(n)={ for(k=1,n, my(seed=k,d=digits(seed)); while(seed<n, seed+=d[1];d=vecextract(concat(d,digits(seed)),"^1"));seed==n&return(k))}

%K nonn,base

%O 1,3

%A _Eric Angelini_ and _M. F. Hasler_, Feb 04 2013