A144153 (0=0, 1=1, 2=2, 3=3, 4=2^2, 5=5, 6=2*3, 7=7, 8=2^3, 9=3^2, 10=2*5, 11=11, 12=2^2*3, ...) becomes (0*0*1, 1*2*2, 3*3*4, 2*2*5, 5*6*2, 3*7*7, 8*2*3, 9*3*2, 10*2*5, 11*11*12, 2*2*3, ...).

0, 4, 36, 20, 60, 147, 48, 54, 100, 1452, 12, 2366, 210, 240, 136, 612, 114, 760, 210, 462, 506, 1104, 225, 260, 702, 252, 28, 25230, 30, 30752, 330, 1122, 1190, 1260, 12, 2738, 1444, 1521, 240, 8405, 252, 12943, 176, 1485, 460, 2162, 4512, 588, 700, 20

Offset

1,2

Links

Table of n, a(n) for n=1..50.

Example

2*2*3 = 12 = a(11),
13*13*14 = 2366 = a(12),
2*7*15 = 210 = a(13),
3*5*16 = 240 = a(14),
2*4*17 = 136 = a(15),
17*18*2 = 612 = a(16),
3*2*19 = 114 = a(17),
etc.

Maple

pflat2 := proc(nmax) local a, ifs, n, p, c ; a := [0, 0, 1, 1] ; for n from 2 to nmax do ifs := ifactors(n)[2] ; a := [op(a), n] ; for p in ifs do # a := [op(a), op(1, p)] ; a := [op(a), op(1, p)] ; if op(2, p) > 1 then a := [op(a), op(2, p)] ; fi; od: od: a ; end proc: pL := pflat2(100) ; for n from 1 to nops(pL)-3 by 3 do printf("%d, ", op(n, pL)*op(n+1, pL)*op(n+2, pL) ) ; od: # R. J. Mathar, Apr 14 2010

Crossrefs

Cf. A002808, A136740, A136811, A143716.

Sequence in context: A366729 A092960 A323515 * A027644 A174426 A198642

Adjacent sequences: A144150 A144151 A144152 * A144154 A144155 A144156

Keyword

nonn

Author

Juri-Stepan Gerasimov, Nov 17 2008

Extensions

Terms from a(18) on replaced by R. J. Mathar, Apr 14 2010

Status

approved