login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A051393 Numbers whose square is expressible as the difference of positive cubes in more than one way. 1
36963, 66248, 157339, 262808, 295704, 519841, 529984, 793117, 990584, 998001, 1258712, 1271403, 1291836, 1788696, 2102464, 2365632, 2688728, 3294486, 3756536, 4158728, 4239872, 4248153, 4620375, 5532247, 5738904, 5938947, 6344936, 6562101, 7095816, 7924672 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..100

EXAMPLE

36963^2 = 1110^3-111^3 = 1332^3-999^3.

PROG

(PARI) mm=577350; cb=vector(mm); for(i=1, mm, cb[i]=i^3); v=vector(10^6); n=vector(10); c=0; mx=10^12; for(i=1, mm-1, for(j=i+1, mm, s=cb[j]-cb[i]; if(s<=mx, if(issquare(s, &r), v[r]++; if(v[r]==2, c++; n[c]=r)), next(2)))); n=vecsort(n); for(i=1, c, print1(n[i] ", ")) \\ Donovan Johnson, Oct 29 2013

CROSSREFS

Cf. A038596, A038597.

Sequence in context: A229509 A223304 A190383 * A233914 A144801 A144812

Adjacent sequences:  A051390 A051391 A051392 * A051394 A051395 A051396

KEYWORD

nonn

AUTHOR

Jud McCranie

EXTENSIONS

Corrected and extended by Ray Chandler, Dec 01 2008

Offset corrected by Donovan Johnson, Oct 29 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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 21 03:06 EST 2019. Contains 320364 sequences. (Running on oeis4.)