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A162700 Numbers n which are concatenations n=x//y such y^2-x^2 = n. 2
48, 3468, 10101, 16128, 34188, 140400, 190476, 216513, 300625, 334668, 416768, 484848, 530901, 2341548, 2661653, 16604400, 33346668, 59809776, 101010101, 3333466668, 4848484848, 4989086476, 18516137328, 30534177388, 56734244853 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Cases with leading zeros of y are not considered.

LINKS

Table of n, a(n) for n=1..25.

EXAMPLE

48=4//8=8^2-4^2. 10101=10//101 = 101^2-10^2. 16128=16//128= 128^2-16^2.

MAPLE

Lton := proc(L) add( op(i, L)*10^(i-1), i=1..nops(L)) ; end:

for n from 10 do dgs := convert(n, base, 10) ; for spli from 1 to nops(dgs)-1 do ydgs := [op(1..spli, dgs)] ; xdgs := [op(spli+1..nops(dgs), dgs)] ; if op(-1, ydgs) <> 0 then x := Lton(xdgs) ; y := Lton(ydgs) ; if y^2-x^2 = n then print(n) ; fi; fi; od: od: # R. J. Mathar, Jul 16 2009

CROSSREFS

Sequence in context: A235903 A208442 A203488 * A027567 A271188 A033475

Adjacent sequences:  A162697 A162698 A162699 * A162701 A162702 A162703

KEYWORD

nonn,base

AUTHOR

Claudio Meller, Jul 11 2009

EXTENSIONS

keyword:base added, definition rephrased, values sorted by R. J. Mathar, Jul 16 2009

More terms from Sean A. Irvine, Nov 19 2009

STATUS

approved

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Last modified August 17 13:03 EDT 2017. Contains 290635 sequences.