A118128 - OEIS

A118128

Numbers n such that the sum of the first n odd composites is palindromic in base 2.

1, 3, 7, 19, 137, 139, 155, 379, 1509, 4877, 9509, 13015, 44819, 75595, 245027, 804463, 1082053, 1154293, 5802669, 10186839, 52333761, 81509017, 130656729, 375417331, 476594459, 1955429145, 9051994251, 12788782787

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..28.

EXAMPLE

The sum of the first 19 odd composites, when written in binary, is the palindrome 1101111011, so 19 is in the sequence.

CROSSREFS

Cf. A058848 (palindromic in base 10).

Sequence in context: A172514 A128024 A245723 * A113875 A111974 A243100

Adjacent sequences: A118125 A118126 A118127 * A118129 A118130 A118131

KEYWORD

nonn,base

AUTHOR

Ryan Propper, May 12 2006

STATUS

approved