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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)

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 *)

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

Patrick De Geest

EXTENSIONS

a(17) corrected by Donovan Johnson, Jan 03 2013

STATUS

approved

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Last modified August 18 10:57 EDT 2017. Contains 290712 sequences.