A376291 Numbers k such that k^k is not a cube and can be expressed as (a^3 + b^3)/2 for positive integers a, b.

76, 112, 172, 364, 427, 532

Offset: 1

Author

Chai Wah Wu, Sep 19 2024

Keywords

• nonn
• more

Comments

Sequence is equal to all terms in A267415 that are not in A376279.

If a or b are allowed to be 0, then 2, 4, 128, 256, 686, 1372, 2000, 4000, 4394, ... are also terms.

Examples

			76^76 is not a cube and is equal to (523974089123227128080087214816032969930445946880^3 + 314384453473936276848052328889619781958267568128^3)/2.
112^112 is not a cube and is equal to (39739105680019344543609706294181022974041418385894471812303329593638887882752^3 + 13246368560006448181203235431393674324680472795298157270767776531212962627584^3)/2.
172^172 is not a cube and is equal to (186302856478727791003189416646781404088735216286873615701287403506960347135763572314025783484358072432973760558663310530664464384^3 + 26614693782675398714741345235254486298390745183839087957326771929565763876537653187717969069194010347567680079809044361523494912^3)/2
		

Crossrefs

Cf. A267415, A376279.