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%I #9 Oct 05 2015 03:01:50
%S 0,1,4,1679616,9,120,14,6568408355712890625,
%T 12748236216396078174437376,462,24,
%U 59952043329758453182876110076904296875,28,960,1122,38587762477395204358312525169472792185842990875244140625,38
%N (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, ...).
%e 6^8 = 1679616 = a(4),
%e 9 = a(5),
%e 10*12 = 120 = a(6),
%e etc.
%p 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:
%p 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
%Y Cf. A141468, A141186, A143677.
%K nonn
%O 1,3
%A _Juri-Stepan Gerasimov_, Nov 17 2008
%E More terms from _R. J. Mathar_, Apr 28 2010