login
A137228
Minimal total number of edges in a polyiamond consisting of n triangular cells.
1
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
1,1
FORMULA
a(n) = (3n + A067628(n))/2.
CROSSREFS
KEYWORD
nonn
AUTHOR
Tanya Khovanova, Mar 07 2008
STATUS
approved