A280428 a(n) = 1729*n^3.

1729, 13832, 46683, 110656, 216125, 373464, 593047, 885248, 1260441, 1729000, 2301299, 2987712, 3798613, 4744376, 5835375, 7081984, 8494577, 10083528, 11859211, 13832000, 16012269, 18410392, 21036743, 23901696, 27015625, 30388904, 34031907, 37955008, 42168581, 46683000

Offset: 1

Author

Sergey Pavlov, Mar 03 2017

Keywords

• nonn
• easy

Comments

Previous name was: Taxi-cab numbers of form n^3*1729; in other words, taxi-cab numbers of form n^3*A001235(1).

Examples

			For n = 11, a(11) = 11^3 * 1729 = 2301299 and a(11) = A001235(67).
		

Links

• Sergey Pavlov, Table of n, a(n) for n = 1..303.
• Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

Crossrefs

Cf. A000578, A001235, A017163, A017271, A017523.

Programs

Mathematica

Array[1729 #^3 &, 30] (* Michael De Vlieger, Mar 04 2017 *)

PARI

vector(30,n,1729*n^3) \\ Derek Orr, Mar 05 2017

Formula

a(n) = n^3 * 1729.

From Chai Wah Wu, Jan 19 2021: (Start)

a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n > 4.

G.f.: x*(1729*x^2 + 6916*x + 1729)/(x - 1)^4. (End)

E.g.f.: 1729*exp(x)*x*(1 + 3*x + x^2). - Stefano Spezia, Apr 05 2025

From Alois P. Heinz, Apr 05 2025: (Start)

a(n) = A017163(n) + A017271(n).

a(n) = A000578(n) + A017523(n). (End)

Extensions

New name from Joerg Arndt, Mar 04 2017

More terms from Sergey Pavlov, Mar 04 2017