A058848 Numbers k such that the sum of the first k odd composites is palindromic.

1, 12, 25, 61, 108, 211, 1344, 2339, 10539, 78409, 283181, 1748747, 1795423, 2386702, 2819089, 179101605, 1923088106, 2822581688, 7794689270, 17381011919, 25635268093, 28780043265, 97973526253

Offset

1,2

Comments

Sequence of odd composite numbers is 9 + 15 + 21 + 25 + 27 + 33 + ... + z. For values of z see A058849.

Links

Table of n, a(n) for n=1..23.

Patrick De Geest, Palindromic Sums

Mathematica

Position[Accumulate[Select[Range[9, 10^7, 2], CompositeQ]], _?(PalindromeQ[#]&)]//Flatten (* The program generates the first 15 terms of the sequence. *) (* Harvey P. Dale, Aug 05 2025 *)

Crossrefs

Cf. A058849, A058850, A262044.

Sequence in context: A229447 A175523 A280391 * A292493 A042869 A041282

Adjacent sequences: A058845 A058846 A058847 * A058849 A058850 A058851

Keyword

nonn,base,more

Author

Patrick De Geest, Dec 15 2000

Extensions

a(20) from Donovan Johnson, Sep 01 2012

a(21)-a(23) from Chai Wah Wu, Dec 06 2019

Comment clarified by Harvey P. Dale, Aug 05 2025

Status

approved