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

1,2

Links

Table of n, a(n) for n=1..52.

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.

Example

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

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} ]

Crossrefs

Sequence in context: A350304 A368612 A265382 * A170907 A143978 A362016

Adjacent sequences: A056735 A056736 A056737 * A056739 A056740 A056741

Keyword

nonn,easy

Author

N. J. A. Sloane, Aug 31 2000

Extensions

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

Status

approved