A123122 Numbers of the form 5i + 7j for some nonnegative integers i and j.

0, 5, 7, 10, 12, 14, 15, 17, 19, 20, 21, 22, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81

Offset

1,2

Comments

The only numbers not of this form belong to the finite set {1, 2, 3, 4, 6, 8, 9, 11, 13, 16, 18, 23}. - Robert G. Wilson v

Starting with 24 all integers are here because 24 = (5-1)*(7-1). - Zak Seidov, Oct 21 2011

Links

Table of n, a(n) for n=1..70.

Index entries for linear recurrences with constant coefficients, signature (2,-1).

Formula

a(n) = n + 11 for n > 12. - Charles R Greathouse IV, Oct 26 2011

Example

a(7) = 17 because 5*2 + 7*1 = 17.

Maple

k:=array(0..47); n:=0; for i from 0 to 7 do for j from 0 to 5 do k[n] := 5*i + 7*j; n:=n+1; end do; end do; for i from 0 to 47 do for j from 0 to 47 do if(k[i] < k[j]) then temp:=k[j]; k[j]:=k[i]; k[i]:=temp; end if; end do; end do; print(k);

Mathematica

Take[Union@ Flatten@ Table[5i + 7j, {i, 0, 35}, {j, 0, 25}], 70] (* Robert G. Wilson v *)
Union@ Flatten@ Table[5i + 7j, {i, 0, 81/5}, {j, 0, (81-5i)/7}] (* Zak Seidov, Oct 22 2011 *)

Prog

(PARI) a(n)=if(n>12, n+11, [0, 5, 7, 10, 12, 14, 15, 17, 19, 20, 21, 22][n]) \\ Charles R Greathouse IV, Oct 26 2011

Crossrefs

Cf. A102701.

Sequence in context: A075275 A245270 A319267 * A256680 A293867 A129189

Adjacent sequences: A123119 A123120 A123121 * A123123 A123124 A123125

Keyword

nonn,easy

Author

Ben Paul Thurston, Sep 29 2006

Extensions

Corrected and extended by Robert G. Wilson v, Sep 30 2006

Status

approved