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 A278935 Least number k = concat(x,y) such that k = n*x*y - x - y, -1 if such a number does not exist. 2
 126, 84, 63, 3231, 42, 4154, 2143, 1143, 4105263158, 6440909347642, 21, 11, 2077, 1077, 18063, 1206, 16056, 105882353, 2052631579, 43304763, 3220454673821, 8044, 12042, 30411, 6039, 5037593985, 321603571507896, 5035, 14033492823, 3033, 17403126122889, 20713030303119 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS MSD of y can be 0. LINKS Table of n, a(n) for n=2..33. Giovanni Resta, terms a(2)-a(100) which are smaller than 10^50 EXAMPLE a(5) = 3231 = concat(3,231) and 5*3*231 - 3 - 231 = 3231; a(18) = 16056 = concat(16,056) and 18*16*56 - 16 - 56 = 16056. MAPLE with(numtheory): P:=proc(q) local j, k, s, t, n, ok; for j from 2 to q do ok:=1; for n from 1 to q do if ok=0 then break; else for k from 1 to ilog10(n) do s:=n mod 10^k; t:=trunc(n/10^k); if j*s*t-s-t=n then print(n); ok:=0; break; fi; od; fi; od; od; end: P(10^6); CROSSREFS Cf. A279058. Sequence in context: A348898 A267403 A267342 * A267395 A176303 A157321 Adjacent sequences: A278932 A278933 A278934 * A278936 A278937 A278938 KEYWORD nonn,base,more AUTHOR Paolo P. Lava, Dec 02 2016 EXTENSIONS a(10), a(11), a(19)-a(22), a(27), a(28), a(30), a(32), a(33) by Giovanni Resta, Dec 05 2016 STATUS approved

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Last modified September 11 21:59 EDT 2024. Contains 375839 sequences. (Running on oeis4.)