A071977 Triangle in which first row is {1}; to get n-th row take first n numbers greater than last number in previous row which are relatively prime to n.

1, 3, 5, 7, 8, 10, 11, 13, 15, 17, 18, 19, 21, 22, 23, 25, 29, 31, 35, 37, 41, 43, 44, 45, 46, 47, 48, 50, 51, 53, 55, 57, 59, 61, 63, 65, 67, 68, 70, 71, 73, 74, 76, 77, 79, 81, 83, 87, 89, 91, 93, 97, 99, 101, 103, 104, 105, 106, 107, 108, 109, 111, 112, 113, 114, 115

Offset

1,2

Links

Reinhard Zumkeller, Rows n=1..120 of triangle, flattened

Example

Triangle begins 1; 3 5; 7 8 10; 11 13 15 17; 18 19 21 22 23; 25 29 31 35 37 41; ....

Mathematica

a = {1}; k = 2; Do[i = 1; While[i < n + 1, If[ GCD[k, n] == 1, a = Append[a, k]; i++ ]; k++ ], {n, 2, 12}]; a

Prog

(Haskell)
a071977 n k = a071977_tabl !! (n-1) !! (k-1)
a071977_row n = a071977_tabl !! (n-1)
a071977_tabl = f 1 [1..] where
   f k xs = ys : f (k+1) (dropWhile (<= last ys) xs) where
     ys  = take k $ filter ((== 1) . (gcd k)) xs
-- Reinhard Zumkeller, Jan 18 2012

Crossrefs

Diagonals give A071978, A071979.

A033291.

Sequence in context: A185602 A225554 A257019 * A183423 A109404 A377286

Adjacent sequences: A071974 A071975 A071976 * A071978 A071979 A071980

Keyword

nonn,tabl

Author

Amarnath Murthy, Jun 18 2002

Extensions

Edited by Robert G. Wilson v, Jun 28 2002

Status

approved