This site is supported by donations to The OEIS Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A225908 Numbers that are both a sum and a difference of two positive cubes. 5
 91, 152, 189, 217, 513, 728, 1027, 1216, 1512, 1736, 2457, 3087, 4104, 4706, 4921, 4977, 5103, 5256, 5824, 5859, 6832, 7657, 8216, 8587, 9728, 10712, 11375, 12096, 12691, 13851, 13888, 14911, 15093, 15561, 16120, 16263, 19000, 19656, 21014, 23058, 23625, 24696 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Solutions x to the equations x = a^3 + b^3 = c^3 - d^3 in positive integers. The intersection of A003325 and A181123. See those sequences for additional comments, references, links and cross-refs. Suggested by Shiraishi's solutions to Gokai Ampon's equation u^3 + v^3 + w^3 = n^3 (transpose a term from the left side to the right side). See A023042 and A226903. An infinite subsequence is (A226904(n)+1)^3 - A226904(n)^3. REFERENCES Shiraishi Chochu (aka Shiraishi Nagatada), Shamei Sampu (Sacred Mathematics), 1826. LINKS Chai Wah Wu, Table of n, a(n) for n = 1..10000 (terms 1..1000 from T. D. Noe) David Eugene Smith and Yoshio Mikami, A History of Japanese Mathematics, Open Court, Chicago, 1914; Dover reprint, 2004; pp. 233-235. Wikipedia (French), Shiraishi Nagatada Wikipedia (German), Shiraishi Nagatada EXAMPLE 3^3 + 4^3 + 5^3 = 6^3, so 3^3 + 4^3 = 91 and 3^3 + 5^3 = 152 and 4^3 + 5^3 = 189 are members. MATHEMATICA nn = 3*10^4; t1 = Union[Flatten[Table[x^3 + y^3, {x, nn^(1/3)}, {y, x, (nn - x^3)^(1/3)}]]]; p = 3; t2 = Union[Reap[Do[n = i^p - j^p; If[n <= nn, Sow[n]], {i, Ceiling[(nn/p)^(1/(p - 1))]}, {j, i}]][[2, 1]]]; Intersection[t1, t2] (* T. D. Noe, Jun 21 2013 *) CROSSREFS Cf. A003325, A023042, A181123, A226903, A226904. Sequence in context: A045934 A051347 A293647 * A159961 A113530 A119148 Adjacent sequences:  A225905 A225906 A225907 * A225909 A225910 A225911 KEYWORD nonn AUTHOR Jonathan Sondow, Jun 21 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified November 18 22:50 EST 2019. Contains 329305 sequences. (Running on oeis4.)