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A281822 Least number k such that (k+n)^2 contains k as a substring. 2

%I #16 Feb 28 2017 03:07:33

%S 1,8,6,1,4,9,62,6,1,1,1,1,1,1,2,2,2,4,1,5,1,2,9,2,4,2,92,9,1,5,1,1,1,

%T 1,1,1,1,1,1,1,1,1,1,1,2,1,2,2,1,2,1,2,2,1,3,1,3,3,1,2,1,4,4,2,4,4,2,

%U 4,1,5,1,1,5,2,4,2,4,2,1,5,1,6,5,2,4,8,6

%N Least number k such that (k+n)^2 contains k as a substring.

%H Paolo P. Lava, <a href="/A281822/b281822.txt">Table of n, a(n) for n = 0..10000</a>

%e a(1) = 8 because (8 + 1)^2 = 9^2 = 81 contains 8 as a substring and it is the least number with this property.

%p with(numtheory): P:= proc(q) local a,b,d,j,k,n,ok;

%p for n from 0 to q do for k from 1 to q do a:=ilog10(k)+1; b:=(n+k)^2; d:=ilog10((k+n)^2)-ilog10(k)+1;

%p ok:=0; for j from 1 to d do if k=(b mod 10^a) then ok:=1; break; else b:=trunc(b/10); fi; od;

%p if ok=1 then print(k); break; fi; od; od; end: P(10^6);

%Y Cf. A018834, A281823.

%K nonn,base,easy

%O 0,2

%A _Paolo P. Lava_, Jan 31 2017

%E Typo in definition corrected by _Harvey P. Dale_, Feb 27 2017.

%E Entries, Maple code and b-file corrected at the suggestion of _Harvey P. Dale_, Feb 28 2017.

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Last modified March 19 03:21 EDT 2024. Contains 370952 sequences. (Running on oeis4.)