A048216 a(n) = T(n,n), where array T is given by A048212.

2, 3, 7, 13, 21, 30, 42, 57, 73, 93, 115, 139, 164, 190, 222, 255, 289, 326, 364, 405, 450, 497, 545, 598, 654, 713, 774, 836, 900, 968, 1037, 1111, 1187, 1264, 1342, 1423, 1507, 1594, 1682, 1771, 1867, 1965, 2065, 2168, 2273, 2379

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Comments

a(1) = 2, a(2) = 3 and a(i) is the next smallest number greater than a(i-1) such that a(i) - a(j) is not a(1) or a(m) or a(m) - a(n) with 1 <= j < i, 1 <= n < m < i. - Ben Paul Thurston, Feb 18 2019

Crossrefs

Cf. A004979, A048212.

Formula

a(n) = A004979(n + 1) - 1. - Sean A. Irvine, Jun 05 2021