A078838 a(n) = Sum_{k=1..(p-1)*(p-2)} floor((k*p)^(1/3)) where p is the n-th prime.

0, 2, 30, 120, 630, 1122, 2760, 3978, 7392, 15498, 19140, 33390, 46020, 53382, 70380, 102102, 142158, 157530, 210210, 251160, 273492, 348348, 405162, 501468, 652080, 737550, 782952, 879270, 930258, 1038072, 1480500, 1626690, 1863540

Offset

1,2

Links

Table of n, a(n) for n=1..33.

Eric Weisstein's World of Mathematics, Prime sums.

Formula

a(n) = (1/4)*(3*p-5)*(p-2)*(p-1) where p = prime(n).

Prog

(PARI) a(n) = my(p=prime(n)); sum(k=1, (p-1)*(p-2), sqrtnint(k*p, 3)); \\ Michel Marcus, Mar 01 2023

Crossrefs

Sequence in context: A193177 A157870 A285991 * A267851 A089288 A232602

Adjacent sequences: A078835 A078836 A078837 * A078839 A078840 A078841

Keyword

nonn

Author

Benoit Cloitre, Dec 08 2002

Extensions

Name edited by Michel Marcus, Mar 01 2023

Status

approved