A144122 (1, 2, 3, 2^2, 5, 2*3, 7, 2^3, 3^2, 2*5, 11, 2^2*3, 13, ...) becomes (0, 1, 4, 6^8, 9, 10*12, 14, 15^16, 18^20, 21*22, 24, 25^26*27, 28, ...).

0, 1, 4, 1679616, 9, 120, 14, 6568408355712890625, 12748236216396078174437376, 462, 24, 59952043329758453182876110076904296875, 28, 960, 1122, 38587762477395204358312525169472792185842990875244140625, 38

Offset

1,3

Links

Table of n, a(n) for n=1..17.

Example

6^8 = 1679616 = a(4),
9 = a(5),
10*12 = 120 = a(6),
etc.

Maple

A141468 := proc(n) if n <=2 then n-1; else for a from procname(n-1)+1 do if not isprime(a) then return a; end if; end do: end if; end proc:
A144122 := proc(nmax) local a, ifs, n, p, c ; printf("0, 1, ") ; c := 3 ; for n from 3 to nmax do ifs := ifactors(n)[2] ; a := 1; for p in ifs do if op(2, p) > 1 then a := a*A141468(c)^A141468(c+1) ; c := c+2 ; else a := a*A141468(c) ; c := c+1 ; fi; od: printf("%d, ", a) ; od: return ; end: A144122(20) ; # R. J. Mathar, Apr 28 2010

Crossrefs

Cf. A141468, A141186, A143677.

Sequence in context: A090096 A218484 A046362 * A058424 A204041 A065248

Adjacent sequences: A144119 A144120 A144121 * A144123 A144124 A144125

Keyword

nonn

Author

Juri-Stepan Gerasimov, Nov 17 2008

Extensions

More terms from R. J. Mathar, Apr 28 2010

Status

approved