A137228 Minimal total number of edges in a polyiamond consisting of n triangular cells.

3, 5, 7, 9, 11, 12, 14, 16, 18, 19, 21, 23, 24, 26, 28, 29, 31, 33, 34, 36, 38, 39, 41, 42, 44, 46, 47, 49, 51, 52, 54, 55, 57, 59, 60, 62, 63, 65, 67, 68, 70, 71, 73, 75, 76, 78, 79, 81, 83, 84, 86, 87, 89, 90, 92, 94, 95, 97, 98, 100, 102, 103, 105, 106, 108, 109, 111, 113

Offset: 1

Author

Tanya Khovanova, Mar 07 2008

Keywords

• nonn

Crossrefs

Cf. A135708, A067628, A000577.

Formula

a(n) = (3n + A067628(n))/2.