A230400 Numbers n such that n = abc = 2(ab+ac+bc) for some positive integers a,b,c.

216, 250, 256, 288, 400, 432, 450, 486, 576, 882

Offset

1,1

Comments

Otherwise said: Volumes of integer-sided cubes equal to their surface area (assuming dimensionless unit of length).

The sequence is a finite subsequence of A055744, A069167, A073539, A090779 and A137845.

Links

Table of n, a(n) for n=1..10.

"Mathematically possible", Volume = Surface Area?, on facebook.com.

Example

The triples (a,b,c) ordered by largest member(s) are (6,6,6), (8,8,4), (10,5,5), (12,6,4), (12,12,3), (15,10,3), (18,9,3), (20,5,4), (24,8,3), (42,7,3).

Prog

(PARI) L=[]; for(a=1, 99, for(b=1, a, for(c=1, b, a*b*c==2*(a*b+b*c+a*c)&&!printf("(%d, %d, %d), ", a, b, c)&&L=concat(L, a*b*c)))); vecsort(L)

Crossrefs

Cf. A229941.

Sequence in context: A018863 A003998 A335544 * A001239 A184088 A348609

Adjacent sequences: A230397 A230398 A230399 * A230401 A230402 A230403

Keyword

nonn,fini,full

Author

M. F. Hasler, Oct 18 2013

Status

approved