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A144192 (0, 1, 2^2, 2*3, 2^3, 3^2, 2*5, 2^2*3, 2*7, 3*5, 2^4, 2*3^2, ...) becomes (0+1, 2+2, 2+3, 2+3, 3+2, 2+5, 2+2, 3+2, 7+3, 5+2, 4+2, 3+2, ...). 0

%I

%S 1,4,5,5,5,7,4,5,10,7,6,5,4,8,9,13,6,7,15,6,4,9,8,7,14,19,12,4,5,21,

%T 16,5,7,10,4,14,7,25,6,10,4,7,20,4,15,6,16,5,10,21,31,5,7,34,9,8,18,5,

%U 13,19,26,7,9,6,4,40,7,4,26,13,16,6,8,6,43,5,12,19,46,31,14,5,7,20,4,26,33

%N (0, 1, 2^2, 2*3, 2^3, 3^2, 2*5, 2^2*3, 2*7, 3*5, 2^4, 2*3^2, ...) becomes (0+1, 2+2, 2+3, 2+3, 3+2, 2+5, 2+2, 3+2, 7+3, 5+2, 4+2, 3+2, ...).

%e 3 + 2 = 5 = a(12),

%e 2 + 2 = 4 = a(13),

%e 5 + 3 = 8 = a(14),

%e 5 + 2 = 7 = a(15),

%e 7 + 2 = 9 = a(16),

%e 11 + 2 = 13 = a(17),

%e 3 + 3 = 6 = a(18),

%e 5 + 2 = 7 = a(19),

%e 2 + 13 = 15 = a(20),

%e 3 + 3 = 6 = a(21),

%e 2 + 2 = 4 = a(22),

%e 7 + 2 = 9 = a(23), etc.

%p pflat := proc(nmax) local a, ifs, n, p, c ; a := [0,1] ; for n from 2 to nmax do if not isprime(n) then ifs := ifactors(n)[2] ; for p in ifs do a := [op(a),op(1,p)] ; if op(2,p) > 1 then a := [op(a),op(2,p)] ; fi; od: fi; od: a ; end: L := pflat(300) ; for n from 1 to nops(L)-2 by 2 do printf("%d,", op(n,L) + op(n+1,L) ) ; end do: # _R. J. Mathar_, Apr 29 2010

%Y Cf. A141468.

%K nonn

%O 1,2

%A _Juri-Stepan Gerasimov_, Nov 20 2008

%E Corrected (a(15) removed, former a(65) replaced) by _R. J. Mathar_, Apr 29 2010

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Last modified October 24 05:38 EDT 2021. Contains 348217 sequences. (Running on oeis4.)