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 A030467 Numbers n such that n^2 is a concatenation of two successive numbers. 22
 428, 573, 727, 846, 7810, 36365, 63636, 326734, 673267, 4545454, 5454547, 47058823, 52941178, 331983807, 332667334, 384615386, 422892898, 475524477, 524475524, 577107103, 615384615, 667332667, 668016194, 719964246, 758241758, 804511280, 810873337, 857142859 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Donovan Johnson and Giovanni Resta, Table of n, a(n) for n = 1..1000  (first 53 terms from Donovan Johnson) Pante Stanica, Squares as concatenation of consecutive integers, Slides, West Coast Number Theory, Dec 17 2017. EXAMPLE 428^2 = 183184, the concatenation of 183 and 184. MATHEMATICA t={}; Do[If[EvenQ[y=Length[x=IntegerDigits[n^2]]] && Differences[FromDigits/@Partition[x, y/2]]=={1}, AppendTo[t, n]], {n, 5.5*10^6}]; t (* Jayanta Basu, May 25 2013 *) Sqrt[#]&/@(Select[FromDigits[Flatten[IntegerDigits/@#]]&/@ (Partition[ Range[735*10^6], 2, 1]), IntegerQ[Sqrt[#]]&]) (* The program takes a long time to run. *) (* Harvey P. Dale, Oct 10 2017 *) PROG (PARI) for(n=1, 10^9, t=eval(concat(Str(n), Str(n+1))); if(issquare(t, &s), print1(s, ", "))); /* Antonio Roldán and Joerg Arndt, Dec 31 2012 */ CROSSREFS Cf. A030465, A030466, A054214, A054215, A054216, A020339, A020340. Sequence in context: A235217 A236383 A224668 * A253505 A173798 A233812 Adjacent sequences:  A030464 A030465 A030466 * A030468 A030469 A030470 KEYWORD nonn,base,nice AUTHOR EXTENSIONS a(17) corrected by Donovan Johnson, Jan 03 2013 STATUS approved

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Last modified October 19 21:28 EDT 2019. Contains 328244 sequences. (Running on oeis4.)