|
| |
|
|
A073612
|
|
Group the natural numbers as (1, 2), (3, 4, 5), (6, 7, 8, 9, 10), (11, 12, 13, 14, 15, 16, 17), ...each group containing p(n) elements. Barring the first, all groups contain odd number of elements and hence have a middle term. Sequence gives middle terms starting from group 2.
|
|
0
| |
|
|
4, 8, 14, 23, 35, 50, 68, 89, 115, 145, 179, 218, 260, 305, 355, 411, 471, 535, 604, 676, 752, 833, 919, 1012, 1111, 1213, 1318, 1426, 1537, 1657, 1786, 1920, 2058, 2202, 2352, 2506, 2666, 2831, 3001, 3177, 3357, 3543, 3735, 3930, 4128, 4333, 4550, 4775
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 2,1
|
|
|
FORMULA
| Difference of the triangular numbers corresponding to the sum of first (n+1) primes and that of first n primes/p(n) for n > 1.
|
|
|
MATHEMATICA
| Table[ Sum[ Prime[i], {i, 1, n}] - Floor[ Prime[n]/2], {n, 2, 50}]
For[lst={}; n1=3; n=2, n<=100, n++, n2=n1+Prime[n]; AppendTo[lst, (n2+n1-1)/2]; n1=n2]; lst
|
|
|
CROSSREFS
| Cf. A034956.
Sequence in context: A063757 A193711 A079328 * A060064 A045474 A100314
Adjacent sequences: A073609 A073610 A073611 * A073613 A073614 A073615
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 05 2002
|
|
|
EXTENSIONS
| Edited by Robert G. Wilson v (rgwv(AT)rgwv.com) and T. D. Noe (noe(AT)sspectra.com), Aug 08 2002
|
| |
|
|
