3,1

Array A[k,n] = k-th Polygorial(n,k) begins:

k..|..Polygorial(n,k)

3..|.1.1..3..18...180....2700.....56700.....1587600......57153600...

4..|.1.1..4..36...576...14400....518400....25401600....1625702400...

5..|.1.1..5..60..1320...46200...2356200...164934000...15173928000...

6..|.1.1..6..90..2520..113400...7484400...681080400...81729648000...

7..|.1.1..7.126..4284..235620..19085220..2137544640..316356606720...

8..|.1.1..8.168..6720..436800..41932800..5577062400..981562982400...

9..|.1.1..9.216..9936..745200..82717200.12738448800.2598643555200...

10.|.1.1.10.270.14040.1193400.150368400.26314470000.6104957040000...

a(3) = 3rd Polygorial number Polygorial(3,3) = A006472(3) = product of the first 3 triangular numbers = 1*3*6 = 18.

a(4) = 4th Polygorial number Polygorial(4,4) = A001044(4) = product of the first 4 squares = 1*4*9*16 = 576.

a(5) = 5th Pentagorial number Polygorial(5,5) = A084939(5) = product of the first 5 pentagonal numbers = 1 * 5 * 12 * 22 * 35 = 46200.

Cf. A006472, A001044, A000680, A084939, A084940, A084941, A084942, A084943, A084944, A085356.

Sequence in context: A126276 A035277 A011906 this_sequence A061079 A003298 A049869

Adjacent sequences: A133398 A133399 A133400 this_sequence A133402 A133403 A133404

easy,more,nonn

Jonathan Vos Post (jvospost3(AT)gmail.com), Nov 25 2007