A062932 a(0) = 0; a(n) = smallest number > a(n-1) such that a(n-1)+a(n) is a palindrome.

0, 1, 2, 3, 4, 5, 6, 16, 17, 27, 28, 38, 39, 49, 50, 51, 60, 61, 70, 71, 80, 81, 90, 91, 100, 102, 110, 112, 120, 122, 130, 132, 140, 142, 150, 153, 160, 163, 170, 173, 180, 183, 190, 193, 200, 204, 210, 214, 220, 224, 230, 234, 240, 244, 250, 255, 260, 265, 270

Offset

0,3

Links

Harry J. Smith, Table of n, a(n) for n = 0..1000

Example

17 is a term hence the next term is 27, as 17 + 27 = 44 is a palindrome, but 17 + 18 = 35 through 17 + 26 = 43 are not palindromes.

Mathematica

palQ[n_] := Block[{d = IntegerDigits@ n}, Reverse@ d == d]; a = {1}; Do[k = a[[n - 1]] + 1; While[! palQ[a[[n - 1]] + k], k++]; AppendTo[a, k], {n, 2, 58}]; {0}~Join~a (* Michael De Vlieger, Oct 05 2015 *)

Prog

(PARI) digitsIn(x)= { local(d); if (x==0, return(1)); d=1 + log(x)\log(10); if (10^d == x, d++, if (10^(d-1) > x, d--)); return(d) }
Palin(x)= { local(y, d, e, f); if (x==0, return(1)); y=x; d=digitsIn(x); t=10^(d - 1); for (i=1, d\2, f=y-10*(y\10); y\=10; e=x\t; x-=t*e; t/=10; if (e!=f, return(0)) ); return(1) }
{ for (n=1, 1000, if (n>1, while (!Palin(a1 + a++), ); a1=a, a=a1=1); write("b062932.txt", n, " ", a) ) } \\ Harry J. Smith, Aug 13 2009

Crossrefs

Cf. A228730 (non-monotonic variant).

Sequence in context: A004835 A037341 A228730 * A347167 A166098 A124365

Adjacent sequences: A062929 A062930 A062931 * A062933 A062934 A062935

Keyword

nonn,base,easy

Author

Amarnath Murthy, Jul 05 2001

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jul 02 2001

Initial a(0)=0 prefixed by M. F. Hasler, Nov 09 2013

Status

approved