A064067 n-th step is to add a(n) to each previous number a(k) (excluding itself, i.e., k < n) to produce n more terms of the sequence, starting with a(0)=1, a(1)=2.

1, 2, 3, 4, 5, 5, 6, 7, 6, 7, 8, 9, 6, 7, 8, 9, 10, 7, 8, 9, 10, 11, 11, 8, 9, 10, 11, 12, 12, 13, 7, 8, 9, 10, 11, 11, 12, 13, 8, 9, 10, 11, 12, 12, 13, 14, 13, 9, 10, 11, 12, 13, 13, 14, 15, 14, 15, 10, 11, 12, 13, 14, 14, 15, 16, 15, 16, 17, 7, 8, 9, 10, 11, 11, 12, 13, 12, 13, 14

Offset

0,2

Links

Table of n, a(n) for n=0..78.

Example

Start with (1,2). So after initial step have (1, *2*, 1+2 = 3), then (1, 2, *3*, 1+3 = 4, 2+3 = 5), then (1, 2, 3, *4*, 5, 1+4 = 5, 2+4 = 6, 3+4 = 7), then (1, 2, 3, 4, *5*, 5, 6, 7, 1+5 = 6, 2+5 = 7, 3+5 = 8, 4+5 = 9), etc.

Crossrefs

Each positive number appears A063895 number of times.

Cf. A064064, A064065, A064066.

Sequence in context: A005375 A138370 A125051 * A202306 A275579 A198292

Adjacent sequences: A064064 A064065 A064066 * A064068 A064069 A064070

Keyword

nonn

Author

Henry Bottomley, Aug 31 2001

Status

approved