A085321 First difference sequence of A003337, i.e., consecutive differences between those consecutive numbers which are sums of three 4th powers.

15, 15, 15, 35, 15, 15, 50, 15, 65, 15, 15, 15, 50, 15, 65, 95, 15, 65, 34, 15, 15, 50, 15, 46, 19, 95, 15, 65, 175, 114, 15, 32, 15, 15, 3, 47, 15, 65, 48, 47, 15, 65, 175, 67, 47, 15, 65, 175, 226, 15, 15, 50, 15, 48, 17, 30, 15, 50, 15, 65, 110, 65, 114, 15, 65, 110, 65

Offset

1,1

Links

Table of n, a(n) for n=1..67.

Example

48 = 16 + 16 + 16, 83 = 81 + 1 + 1, 81 - 48 = 35 = a(4);
Certain differences occur consequently like 15, 30, 31, 32, 49, 50, 64, 65, 175, etc.;
Distance of closest neighbors equals 1,
like those of 7202 = 6561 + 625 + 16 and 7203 = 2401 + 2401 + 2401.

Mathematica

{m=12, k=5, m^k}; t=Union[Flatten[Table[Table[Table[Table[w^k+q^k+t^k+u^k, {w, 1, m}], {q, 1, m}], {t, 1, m}], {u, 1, m}]]]; Length[t]; dt=Delete[ -RotateRight[t]+t, 1]; Sort[dt]

Crossrefs

Cf. A003337, A003327-A003399.

Sequence in context: A225917 A140806 A099610 * A239315 A003890 A040211

Adjacent sequences: A085318 A085319 A085320 * A085322 A085323 A085324

Keyword

nonn

Author

Labos Elemer, Jul 01 2003

Status

approved