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 A259379 Numbers n of the form a - b + c, such that n^3 equals the decimal concatenation a//b//c and numbers n, b, and c have the same number of digits. 2
 155, 209, 274, 286, 287, 351, 364, 428, 573, 637, 715, 727, 846, 923, 1095, 1096, 2191, 8905, 18182, 18183, 81818, 81819, 326734, 336634, 663367, 673267, 2727273, 2727274, 4545454, 5454547, 7272727, 23529411, 23529412, 76470589 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS This sequence is infinite because it has several infinite subsequences. For example: 274, 326734, 332667334, 3..326..673..34 etc.; 364, 336634, 333666334, 3..36..63..34 etc.; 637, 663367, 666333667, 6..63..36..67 etc.; 727, 673267, 667332667, 6..673..326..67 etc. Note that: 274 + 727 = 364 + 637 = 1001 and 326734 + 673267 = 336634 + 663367 = 1000001. Many numbers come in pairs, like: (286, 287), (1095, 1096), (18182, 18183) but also bigger number (140017877, 140017878) and (859982123, 859982124). 140017877 + 859982124 = 140017878 + 859982123 = 1000000001. LINKS Pieter Post, Table of n, a(n) for n = 1..189 EXAMPLE 155^3 = 3723875 and 155 = 3 - 723 + 875. 715^3 = 365525875 and 715 = 365 - 525 + 875. PROG (Python) def modb(n, m): ...kk = 0 ....l=1 ....while n > 0: ........na=int(n%m) ........l=l+1 ........kk= kk+((-1)**l)*na ........n =int(n//m) ....return kk for n in range (100, 10**9): ....ll= len(str(n)) ....if modb(n**3, 10**ll)==n: .........print (n) (PARI) isok(n)=nb = #digits(n, 10); if (a = n^3 \ 10^(2*nb), c = n^3 % 10^nb; b = (n^3 - a*10^(2*nb))\10^nb; n^3 == (a-b+c)^3; ); \\ Michel Marcus, Aug 05 2015 CROSSREFS Cf. A056733, A101311, A118937, A118938, A228381, A257796, A258482. Sequence in context: A248657 A159258 A214472 * A122475 A252805 A089256 Adjacent sequences:  A259376 A259377 A259378 * A259380 A259381 A259382 KEYWORD nonn,base AUTHOR Pieter Post, Jul 22 2015 STATUS approved

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Last modified August 3 13:21 EDT 2020. Contains 336198 sequences. (Running on oeis4.)