A056738 Positions where 2's occur in A056731.

1, 4, 8, 13, 20, 28, 37, 47, 59, 72, 86, 101, 117, 135, 154, 174, 195, 217, 240, 264, 290, 317, 345, 374, 404, 435, 467, 500, 535, 571, 608, 646, 685, 725, 766, 808, 851, 896, 942, 989, 1037, 1086, 1136, 1187, 1239, 1292, 1346, 1402, 1459, 1517, 1576, 1636

Offset: 1

Author

N. J. A. Sloane, Aug 31 2000

Keywords

• nonn
• easy

Examples

			a(9) = a(8) + 8 + the number of a(k)'s <= 8 = 47 + 8 + 1 + 3 ( a(3) is <= 8) = 59.
		

Programs

Mathematica

f[1] = 1; f[n_] := f[n] = Block[ {k = 1}, While[ f[k] < n, k++ ]; Return[ f[n - 1] + n + k ]]; Table[ f[n], {n, 0, 60} ]

Formula

A056738(n) = A005228(n)+A030124(n)-n-1.

a(n+1) = a(n) + (n+1) + the number of a(k)'s <= n, 1 <= k <= n and a(1) = 1.

Extensions

More terms from Robert G. Wilson v, Nov 25 2001