A309325 Numbers that are the sum of two successive palindromes.

1, 3, 5, 7, 9, 11, 13, 15, 17, 20, 33, 55, 77, 99, 121, 143, 165, 187, 200, 212, 232, 252, 272, 292, 312, 332, 352, 372, 393, 414, 434, 454, 474, 494, 514, 534, 554, 574, 595, 616, 636, 656, 676, 696, 716, 736, 756, 776, 797, 818, 838, 858, 878, 898, 918, 938, 958, 978

Offset

1,2

Links

Table of n, a(n) for n=1..58.

Index entries for sequences related to palindromes

Formula

a(n) = A002113(n) + A002113(n+1).

Mathematica

Total /@ Partition[Select[Range[0, 500], PalindromeQ], 2, 1]

Prog

(Python)
from itertools import chain, count, islice
def A309325_gen(): # generator of terms
    c = 0
    for a in chain.from_iterable(chain((int((s:=str(d))+s[-2::-1]) for d in range(10**l, 10**(l+1))), (int((s:=str(d))+s[::-1]) for d in range(10**l, 10**(l+1)))) for l in count(0)):
        yield c+(c:=a)
A309325_list = list(islice(A309325_gen(), 20)) # Chai Wah Wu, Jun 23 2022

Crossrefs

Cf. A002113, A046489, A046497, A260255, A261906.

Sequence in context: A061808 A248608 A362680 * A368729 A192863 A143450

Adjacent sequences: A309322 A309323 A309324 * A309326 A309327 A309328

Keyword

nonn,base

Author

Ilya Gutkovskiy, Jul 23 2019

Status

approved