A343086 a(n) is the smallest number that is the sum of n positive 4th powers in four ways.

5978882, 236674, 20995, 6626, 2925, 2925, 2854, 1620, 1621, 777, 778, 779, 780, 781, 782, 528, 529, 515, 516, 517, 518, 519, 520, 521, 522, 523, 524, 525, 526, 512, 513, 514, 515, 516, 517, 518, 519, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531

Offset

3,1

Comments

This is r(n,4,4) in Alter's notation.

Links

Table of n, a(n) for n=3..51.

R. Alter, Computations and generalizations on a remark of Ramanujan, pp. 182-196 of "Analytic Number Theory (Philadelphia, 1980)", ed. M. I. Knopp, Lect. Notes Math., Vol. 899, 1981. See Table 12, page 194.

Index entries for linear recurrences with constant coefficients, signature (2,-1).

Formula

a(n) = n + 480 for n >= 32.

Example

a(3) = 5978882 = 3^4 + 40^4 + 43^4 = 8^4 + 37^4 + 45^4 = 15^4 + 32^4 + 47^4 = 23^4 + 25^4 + 48^4.
a(4) = 236674 = 1^4 + 2^4 + 7^4 + 22^4 = 3^4 + 6^4 + 18^4 + 19^4 = 7^4 + 14^4 + 16^4 + 19^4 = 8^4 + 16^4 + 17^4 + 17^4.

Crossrefs

Cf. A085559, A123075, A342897, A343077, A343082, A343084, A343085.

Sequence in context: A205262 A183022 A183021 * A344277 A344278 A184385

Adjacent sequences: A343083 A343084 A343085 * A343087 A343088 A343089

Keyword

nonn

Author

Sean A. Irvine, Apr 04 2021

Status

approved