STATUS
reviewed
approved
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reviewed
approved
proposed
reviewed
editing
proposed
Alternately odd and even numbers so such that a(n) is the least number not included earlier and has a common factor with a(n-1).
approved
editing
editing
approved
approved
editing
_Amarnath Murthy (amarnath_murthy(AT)yahoo.com), _, Feb 16 2004
A091780 := proc(nmax) local a, nstrt; a := [3] ; while nops(a) < nmax do if nops(a) mod 2 = 0 then nstrt := 5; else nstrt := 4 ; fi ; while nstrt in a or gcd(nstrt, op(-1, a)) < 2 do nstrt := nstrt+2 ; od ; a := [op(a), nstrt] ; od ; a ; end: A091780(80) ; - _R. J. Mathar (mathar(AT)strw.leidenuniv.nl), _, Jul 26 2007
More terms from _R. J. Mathar (mathar(AT)strw.leidenuniv.nl), _, Jul 26 2007
A091780 := proc(nmax) local a, nstrt; a := [3] ; while nops(a) < nmax do if nops(a) mod 2 = 0 then nstrt := 5; else nstrt := 4 ; fi ; while nstrt in a or gcd(nstrt, op(-1, a)) < 2 do nstrt := nstrt+2 ; od ; a := [op(a), nstrt] ; od ; a ; end: A091780(80) ; - Richard R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 26 2007
nonn,new
nonn
More terms from Richard R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 26 2007
3, 6, 9, 12, 15, 10, 5, 20, 25, 30, 21, 14, 7, 28, 35, 40, 45, 18, 27, 24, 33, 22, 11, 44, 55, 50, 65, 26, 13, 52, 39, 36, 51, 34, 17, 68, 85, 60, 57, 38, 19, 76, 95, 70, 49, 42, 63, 48, 69, 46, 23, 92, 115, 80, 75, 54, 81, 66, 77, 56, 91, 78, 87, 58, 29, 116, 145, 90, 93, 62
A091780 := proc(nmax) local a, nstrt; a := [3] ; while nops(a) < nmax do if nops(a) mod 2 = 0 then nstrt := 5; else nstrt := 4 ; fi ; while nstrt in a or gcd(nstrt, op(-1, a)) < 2 do nstrt := nstrt+2 ; od ; a := [op(a), nstrt] ; od ; a ; end: A091780(80) ; - Richard J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 26 2007
more,nonn,new
nonn
More terms from Richard J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 26 2007