cp's OEIS Frontend

A069555 a(n) = smallest non-palindromic number k such that k and its digit reversal are divisible by n, or 0 if n is a multiple of 10.

%I A069555 #6 Dec 05 2013 19:55:15
%S A069555 10,20,12,40,50,24,70,80,18,0,110,48,1495,2072,510,2192,1156,216,1710,
%T A069555 0,168,220,1610,840,5200,2496,1998,2520,2320,0,1178,2304,132,2720,
%U A069555 5075,216,1110,2166,1677,0,1066,2436,9890,440,540,4140,1410,2304,3430,0,1479
%N A069555 a(n) = smallest non-palindromic number k such that k and its digit reversal are divisible by n, or 0 if n is a multiple of 10.
%e A069555 a(12) = 48 as 12 divides 48 as well as 84.
%p A069555 np := proc(N::posint,i::posint) local d,e; description "if 'N' is not palindromic and 'i' divides both 'N' and its reverse then returns 'true', else 'false'"; d := convert(N,base,10); e := sum(d[j]*10^(nops(d)-j),j=1..nops(d)); if N=e then return false else if N mod i=0 and e mod i=0 then return true else return false fi; fi; end proc; nps := proc(J::posint,K::posint) local f,F,FU,i; description "returns the sequence of smallest numbers that satisfy 'np' (or number is 0 if the sequence position is divisible by 10) starting at sequence position 'J' and checking numbers up to 'K'; to get a sequence from 1 to the maximum position allowable by 'K', set 'J=1'."; f := (i,M)->`if`(i mod 10=0,0,min(seq(`if`(np(N,i)=true,N,NULL),N=i..M))); i := J; while f(i,K)<>infinity do F(i) := `if`(i mod 10=0,0,f(i,K)); i := i+1 od; FU := [seq(F(ii),ii=J..i-1)]; return FU,`if`(FU=[],printf("no numbers found; try raising 'K'."),printf("the sequence from positions %d to %d.",J,i-1)); end proc;
%Y A069555 Cf. A069554.
%K A069555 nonn,base
%O A069555 1,1
%A A069555 _Amarnath Murthy_, Mar 22 2002
%E A069555 More terms from Francois Jooste (phukraut(AT)hotmail.com), Mar 06 2003