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approved

A094747 := proc(nmax) local a, diffs, d; a := [3] ; diffs := {} ; while nops(a) < nmax do d := 2 ; while true do if isprime(op(-1, a)-d) and not op(-1, a)-d in a and not abs(d) in diffs then a := [op(a), op(-1, a)-d] ; diffs := diffs union {d} ; break ; elif isprime(op(-1, a)+d) and not op(-1, a)+d in a and not abs(d) in diffs then a := [op(a), op(-1, a)+d] ; diffs := diffs union {d} ; break ; else d := d+2 ; fi ; od ; od; RETURN(a) ; end: A094747(100) ; - _# _R. J. Mathar_, Jul 29 2007

approved

editing

_Amarnath Murthy (amarnath_murthy(AT)yahoo.com), _, May 24 2004

We interpret the definition as saying that we find a(n+1) from a(n) by testing a(n)-+2*d (first the minus, then the plus, d=1,2,3,4...., d not used before) for primality and for not already being on the list. This creates a list of odd primes, but there is no proof (yet) that all odd primes are in the sequence. - _R. J. Mathar (mathar(AT)strw.leidenuniv.nl), _, Jul 29 2007

A094747 := proc(nmax) local a, diffs, d; a := [3] ; diffs := {} ; while nops(a) < nmax do d := 2 ; while true do if isprime(op(-1, a)-d) and not op(-1, a)-d in a and not abs(d) in diffs then a := [op(a), op(-1, a)-d] ; diffs := diffs union {d} ; break ; elif isprime(op(-1, a)+d) and not op(-1, a)+d in a and not abs(d) in diffs then a := [op(a), op(-1, a)+d] ; diffs := diffs union {d} ; break ; else d := d+2 ; fi ; od ; od; RETURN(a) ; end: A094747(100) ; - _R. J. Mathar (mathar(AT)strw.leidenuniv.nl), _, Jul 29 2007

More terms from _R. J. Mathar (mathar(AT)strw.leidenuniv.nl), _, Jul 29 2007

We interpret the definition as saying that we find a(n+1) from a(n) by testing a(n)-+2*d (first the minus, then the plus, d=1,2,3,4...., d not used before) for primality and for not already being on the list. This creates a list of odd primes, but there is no proof (yet) that all odd primes are in the sequence. - Richard R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 29 2007

A094747 := proc(nmax) local a, diffs, d; a := [3] ; diffs := {} ; while nops(a) < nmax do d := 2 ; while true do if isprime(op(-1, a)-d) and not op(-1, a)-d in a and not abs(d) in diffs then a := [op(a), op(-1, a)-d] ; diffs := diffs union {d} ; break ; elif isprime(op(-1, a)+d) and not op(-1, a)+d in a and not abs(d) in diffs then a := [op(a), op(-1, a)+d] ; diffs := diffs union {d} ; break ; else d := d+2 ; fi ; od ; od; RETURN(a) ; end: A094747(100) ; - Richard R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 29 2007

nonn,new

nonn

More terms from Richard R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 29 2007

3, 5, 11, 7, 17, 29, 37, 23, 41, 61, 83, 67, 43, 71, 97, 127, 163, 131, 89, 137, 103, 59, 19, 73, 13, 79, 149, 199, 251, 307, 269, 223, 281, 349, 277, 353, 431, 367, 293, 373, 311, 229, 313, 227, 139, 47, 151, 241, 337, 239, 347, 449, 563, 463, 557, 673, 797, 691, 809

We interpret the definition as saying that we find a(n+1) from a(n) by testing a(n)-+2*d (first the minus, then the plus, d=1,2,3,4...., d not used before) for primality and for not already being on the list. This creates a list of odd primes, but there is no proof (yet) that all odd primes are in the sequence. - Richard J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 29 2007

A094747 := proc(nmax) local a, diffs, d; a := [3] ; diffs := {} ; while nops(a) < nmax do d := 2 ; while true do if isprime(op(-1, a)-d) and not op(-1, a)-d in a and not abs(d) in diffs then a := [op(a), op(-1, a)-d] ; diffs := diffs union {d} ; break ; elif isprime(op(-1, a)+d) and not op(-1, a)+d in a and not abs(d) in diffs then a := [op(a), op(-1, a)+d] ; diffs := diffs union {d} ; break ; else d := d+2 ; fi ; od ; od; RETURN(a) ; end: A094747(100) ; - Richard J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 29 2007

more,nonn,new

nonn

More terms from Richard J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 29 2007

Rearrangement of odd primes so that absolute successive differences are the least distinct even numbers. Priority is given to the least successive difference that has not occurred earlier.

3, 5, 11, 7, 17, 29, 37, 23, 41, 61, 83, 67

1,1

Cf. A094748.

more,nonn

Amarnath Murthy (amarnath_murthy(AT)yahoo.com), May 24 2004

approved