1,2

Terms with even indices are cubes n^3 with n=2,3,... (all integers >1), while terms with odd indices are square m^3 with m=1,3,6,9,12,15,19,23,28,32,37,42,47,53,59,65,71,77,83,90,97,104,111,118,126,133,141,149,157,165,173,182,190,199,208,217,226,235,244,253,263,273,282,292,302,312,323,333,344,354,365,375,386,397,408,420,431,442,454,465,477,489,501,513,525,537,549,561,574,586,599,611,624,637,650,663,676,689,703,716,730,743,757,770,784,798,812,826,840,854,869,883,897,912,926,941,956,971,986,1001; cf. A077121 Number of integer squares <= n^3.

a(1)=1 considered as square,

a(2)=8 = least cube >a(1);

a(3)=9 = least square >a(2),

a(4)=27 = least cube >a(3),

a(5)=36 = least square >a(4),

a(6)=64 = least cube >a(5),

a(7)=81 = least square >a(6),

a(8)=125 = least cube >a(7).

Cf. A077113, A077121.

Sequence in context: A042311 A003997 A114090 this_sequence A046874 A038344 A050771

Adjacent sequences: A139750 A139751 A139752 this_sequence A139754 A139755 A139756

nonn

Zak Seidov (zakseidov(AT)yahoo.com), May 19 2008