|
| |
|
|
A135051
|
|
Pyramid game person numbers that have integer solutions for: Solve[m(m + 1)/2 + 1 - n == 0, m].
|
|
0
| |
|
|
7, 79, 191, 407, 631, 991, 1327, 1831, 2279, 2927, 3487, 4279, 4951, 5887, 6671, 7751, 8647, 9871
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| This result comes from looking for "perfect Pyramids":
Solve[m(m + 1)/2 + 1 - n == 0, m]
f[n_] = (1/2) (-1+ Sqrt[ -7 + 8 n])
Integer solutions have the form such that:
IntegerQ[2*Sqrt[ -7 + 8*n]] && Mod[n - 7, 8] == 0
|
|
|
FORMULA
| a(n) = If[ IntegerQ[2*Sqrt[ -7 + 8*n]] && Mod[n - 7, 8] == 0, n]
|
|
|
MATHEMATICA
| Flatten[Table[If[ IntegerQ[2*Sqrt[ -7 + 8*n]] && Mod[n - 7, 8] == 0, n, {}], {n, 1, 10000}]]
|
|
|
CROSSREFS
| Sequence in context: A140613 A139945 A023285 * A201860 A176130 A014232
Adjacent sequences: A135048 A135049 A135050 * A135052 A135053 A135054
|
|
|
KEYWORD
| nonn,uned
|
|
|
AUTHOR
| Roger Bagula (rlbagulatftn(AT)yahoo.com), Jan 31 2008
|
| |
|
|
