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 A346287 Numbers that are of both forms x^k+x+1 and x^k-(x+1) with k>=2 and x>=0. 0
 1, 11, 13, 19, 131, 5851, 416833471 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..7. EXAMPLE 1 = 2^2-(2+1) = 0^2+(0+1) 11 = 4^2-(4+1) = 2^3+(2+1) 13 = 2^4-(2+1) = 3^2+(3+1) 19 = 5^2-(5+1) = 2^4+(2+1) 131 = 12^2-(12+1) = 5^3+(5+1) 5851 = 77^2-(77+1) = 18^3+(18+1) 416833471 = 20417^2-(20417+1) = 747^3+(747+1) MAPLE N:= 10^11: # for terms <= N R:= {3}: for k from 2 to ilog2(N-1) do R:= R union {seq(x^k+x+1, x=2..floor(N^(1/k)))} od: A:= {1}: for k from 2 to ilog2(N+3) do for x from 2 do r:= x^k-(x+1); if r > N then break fi; if member(r, R) then A:= A union {r} fi od od: sort(convert(A, list)); CROSSREFS Cf. A253913. Sequence in context: A102907 A235479 A089774 * A330975 A351841 A257864 Adjacent sequences: A346284 A346285 A346286 * A346288 A346289 A346290 KEYWORD nonn,more AUTHOR J. M. Bergot and Robert Israel, Jul 12 2021 STATUS approved

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Last modified May 30 05:52 EDT 2023. Contains 363044 sequences. (Running on oeis4.)