A143680 a(n) = (prime(n)^3 - prime(n^3))/2.

3, 4, 11, 16, 320, 438, 1302, 1594, 3324, 8235, 9417, 17950, 24759, 27349, 36252, 55002, 78861, 84711, 115866, 138056, 146440, 190374, 220857, 277626, 370572, 417629, 435933, 488096, 507799, 565157, 850338, 930999, 1072092, 1107343

Offset: 1

Author

Juri-Stepan Gerasimov, Nov 01 2008

Keywords

• nonn

Examples

			If n=1, then (prime(1)^3-prime(1^3))/2 = (8-2)/2 = 6/2 = 3 = a(1).
If n=2, then (prime(2)^3-prime(2^3))/2 = (27-19)/2 = 8/2 = 4 = a(2).
If n=3, then (prime(3)^3-prime(3^3))/2 = (125-103)/2 = 22/2 = 11 = a(3).
If n=4, then (prime(4)^3-prime(4^3))/2 = (343-311)/2 = 32/2 = 16 = a(4).
If n=5, then (prime(5)^3-prime(5^3))/2 = (1331-691)/2 = 640/2 = 320 = a(5), etc.
		

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040.

Cf. A030078, A055875. [R. J. Mathar, Nov 05 2008]

Programs

Magma

[(NthPrime(n)^3 -NthPrime(n^3))/2: n in [1..40]]; // Vincenzo Librandi, Sep 15 2015

Maple

A143680 := proc(n) option remember ; local p; (ithprime(n)^3-ithprime(n^3))/2 ; end: for n from 1 to 40 do printf("%d,",A143680(n)) ; od: # R. J. Mathar, Nov 05 2008

Mathematica

Table[(Prime[n]^3 - Prime[n^3]) / 2, {n, 50}] (* Vincenzo Librandi, Sep 15 2015 *)

PARI

a(n) = (prime(n)^3 -prime(n^3))/2; \\ Michel Marcus, Sep 15 2015

Sage

[(nth_prime(n)^3 - nth_prime(n^3))/2 for n in (1..40)] # G. C. Greubel, May 29 2021

Extensions

More terms from R. J. Mathar, Nov 05 2008