A178741 a(1)=2. For a(n)+1, differences must be strictly increasing and consecutive terms are relatively prime

2, 3, 5, 8, 13, 19, 26, 35, 46, 59, 73, 88, 105, 124, 145, 167, 190, 217, 246, 277, 309, 343, 379, 416, 457, 499, 542, 587, 633, 680, 729, 779, 830, 883, 937, 992, 1049, 1107, 1166, 1227, 1289, 1352, 1419, 1487, 1556, 1627, 1699, 1772, 1847, 1923, 2000, 2079

Offset

1,1

Links

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

Example

a(5) cannot be 12 because 8 and 12 are not relatively prime

Mathematica

f[s_] := Block[{k = 2 s[[ -1]] - s[[ -2]] + 1}, While[ GCD[k, s[[ -1]]] > 1, k++ ]; Append[s, k]]; Rest@ Nest[f, {2, 2}, 51] (* Robert G. Wilson v, Jun 09 2010 *)

Crossrefs

Sequence in context: A120761 A355513 A281967 * A308929 A308994 A326469

Adjacent sequences: A178738 A178739 A178740 * A178742 A178743 A178744

Keyword

nonn

Author

J. Lowell, Jun 08 2010

Extensions

a(11) onwards from Robert G. Wilson v, Jun 09 2010

Status

approved