A079775 Triangle in A079774 read by rows.

4, 6, 8, 8, 10, 12, 9, 12, 15, 18, 10, 12, 14, 16, 18, 12, 14, 16, 18, 20, 22, 14, 16, 18, 20, 22, 24, 26, 15, 18, 21, 24, 27, 30, 33, 36, 16, 18, 20, 22, 24, 26, 28, 30, 32, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 21, 24, 27, 30, 33

Offset

1,1

Links

Table of n, a(n) for n=1..71.

Example

Triangle begins:
   4
   6  8
   8 10 12
   9 12 15 18
  10 12 14 16 18
  12 14 16 18 20 22
  ...

Maple

A002808 := proc(n) local resul, i ; i := 1 ; resul := 4 ; while i < n do resul := resul+1 ; while isprime(resul) do resul := resul+1 ; od ; i := i+1 ; od; RETURN(resul) ; end: A079775 := proc(n) local a, anxt, atst ; a := [A002808(n)] ; while nops(a) < n do anxt := op(-1, a)+1 ; atst := [ op(a), anxt] ; while igcd(op(atst)) = 1 do anxt := anxt+1 ; atst := [ op(a), anxt] ; od ; a := [op(a), anxt] ; od; RETURN(a) ; end: for n from 1 to 20 do arow := A079775(n) : for m from 1 to nops(arow) do printf("%d, ", op(m, arow)) ; od ; # R. J. Mathar, Apr 01 2007

Mathematica

A002808[n_] := Module[{resul, i}, i = 1; resul = 4; While[i < n, resul++; While[PrimeQ[resul], resul++]; i++]; Return[resul]];
A079775[n_] := Module[{a, anxt, atst}, a = {A002808[n]}; While[Length[a] < n, anxt = a[[-1]]+1; atst = Append[a, anxt]; While[GCD @@ atst == 1, anxt++; atst = Append[a, anxt]]; a = Append[a, anxt]]; Return[a]];
Table[A079775[n], {n, 1, 20}] // Flatten (* Jean-François Alcover, Mar 27 2024, after R. J. Mathar *)

Crossrefs

Cf. A002808, A079774, A079776.

Sequence in context: A095253 A027709 A196358 * A247654 A262767 A104173

Adjacent sequences: A079772 A079773 A079774 * A079776 A079777 A079778

Keyword

nonn,tabl

Author

Amarnath Murthy, Jan 31 2003

Extensions

Corrected and extended by R. J. Mathar, Apr 01 2007

Status

approved