A110222 Palindromic numbers which are not the absolute difference of a cube and a square.

6, 66, 77, 88, 111, 181, 202, 363, 383, 434, 454, 474, 494, 555, 565, 595, 606, 646, 666, 707, 717, 747, 787, 818, 838, 858, 929, 949, 959, 979, 989, 1221, 1551, 1661, 2002, 2442, 2662, 3003, 3443, 3773, 3883, 4114, 4334, 4444, 4774, 4884, 5005, 5115, 5335

Offset

1,1

Comments

The palindromes in A110223.

Links

Table of n, a(n) for n=1..49.

Mathematica

NextPalindrome[n_] := Block[ {l = Floor[ Log[10, n] + 1], idn = IntegerDigits[n]}, If[ Union[ idn] == {9}, Return[n + 2], If[l < 2, Return[n + 1], If[ FromDigits[ Reverse[ Take[ idn, Ceiling[l/2]]]] > FromDigits[ Take[ idn, -Ceiling[l/2]]], FromDigits[ Join[ Take[ idn, Ceiling[l/2]], Reverse[ Take[ idn, Floor[l/2]]]]], idfhn = FromDigits[ Take[ idn, Ceiling[l/2]]] + 1; idp = FromDigits[ Join[ IntegerDigits[ idfhn], Drop[ Reverse[ IntegerDigits[ idfhn]], Mod[l, 2]]]]]]]]; t1 = NestList[ NextPalindrome, 0, 130]; t2 = Union[ Flatten[ Table[ Select[ Table[ Abs[n^3 - m^2], {m, 0, 10000}], # < 10^3 &], {n, -5000, 5000}]]]; Take[ Complement[t1, Intersection[t1, t2]], 50]

Crossrefs

Cf. A109879, A074981, A110223.

Sequence in context: A359854 A284067 A137121 * A119230 A372547 A122780

Adjacent sequences: A110219 A110220 A110221 * A110223 A110224 A110225

Keyword

base,nonn

Author

Robert G. Wilson v, Jul 16 2005

Status

approved