0,2

All members are palindromes A002113. First five members are mentioned in A129868.

Also, binary representation of A129868.

a(A090748(n)) is equal to A138831(n), the n-th perfect number minus 1, written in base 2.

n ........ a(n) ... A129868(n)

0 ......... 0 ......... 0

1 ........ 101 ........ 5

2 ....... 11011 ....... 27

3 ...... 1110111 ...... 119

4 ..... 111101111 ..... 495

5 .... 11111011111 .... 2015

6 ... 1111110111111 ... 8127

Cyclops numbers: A134808. Cf. A002113, A129868.

Cf. A000396, A090748, A135627, A138831.

Sequence in context: A100027 A097727 A083981 this_sequence A138831 A068160 A082435

Adjacent sequences: A138145 A138146 A138147 this_sequence A138149 A138150 A138151

easy,nonn

Omar E. Pol (info(AT)polprimos.com), Mar 18 2008m Apr 08 2008