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 A281823 Least number k such that (k-n)^2 contains k as a substring. 2
 1, 12, 1, 16, 108, 1, 4, 2, 116, 3, 1, 1, 1, 1, 1, 1, 4, 2, 2, 2, 1, 3, 1, 9, 4, 2, 4, 2, 5, 2, 1, 6, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 2, 2, 1, 2, 1, 2, 2, 1, 2, 1, 3, 2, 1, 3, 1, 2, 3, 3, 3, 2, 4, 3, 1, 4, 1, 1, 4, 2, 3, 2, 4, 2, 1, 2, 1, 4, 2, 6 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Paolo P. Lava, Table of n, a(n) for n = 0..10000 EXAMPLE a(1) = 12 because (12 - 1)^2 = 11^2 = 121 contains 12 as a substring and it is the least number with this property. MAPLE with(numtheory): P:= proc(q) local a, b, d, j, k, n, ok; 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; 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; if ok=1 then print(k); break; fi; od; od; end: P(10^6); MATHEMATICA nk[n_]:=Module[{k=1}, While[SequenceCount[IntegerDigits[(k-n)^2], IntegerDigits[ k]]==0, k++]; k]; Array[lnk, 90, 0] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 13 2021 *) CROSSREFS Cf. A018834, A281822. Sequence in context: A070649 A255864 A056583 * A139724 A040155 A036185 Adjacent sequences: A281820 A281821 A281822 * A281824 A281825 A281826 KEYWORD nonn,base,easy AUTHOR Paolo P. Lava, Jan 31 2017 EXTENSIONS Typo in definition corrected by Harvey P. Dale, Feb 27 2017. Entries, Maple code and b-file corrected at the suggestion of Harvey P. Dale, Feb 28 2017. STATUS approved

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Last modified September 9 19:57 EDT 2024. Contains 375765 sequences. (Running on oeis4.)