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 A066133 In base 2, twelve 'Reverse and Add' steps are needed to reach a palindrome. 1
 1027, 1139, 1181, 1229, 1433, 1481, 1537, 1649, 1951, 1983, 1999, 2031, 2051, 3073, 3103, 3215, 3351, 3463, 3611, 3639, 3671, 3723, 3751, 3783, 3839, 3859, 3971, 4087, 4103, 4121, 4141, 4187, 4237, 4269, 4327, 4331, 4333, 4361, 4427, 4603, 4625, 4645 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The analogue of A065217 in base 2. The number of steps starts at 0, so palindromes (cf. A006995) are excluded. LINKS Harry J. Smith, Table of n, a(n) for n=1,...,1000 PROG (PARI) Rev(x)= { local(d, r=0); while (x>0, d=x%10; x\=10; r=r*10 + d); return(r) } 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(d, e, f, i, t, y); 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) } baseE(x, b)= { local(d, e=0, f=1); while (x>0, d=x-b*(x\b); x\=b; e+=d*f; f*=10); return(e) } baseI(x, b)= { local(d, e=0, f=1); while (x>0, d=x-10*(x\10); x\=10; e+=d*f; f*=b); return(e) } calcB(p)= { local(b, r); b=baseE(p, 2); r=Rev(b); d=baseI(r, 2) + p; b=baseE(d, 2); return(b); } { n=0; for (m=1, 10^9, d=m; t=1; b=baseE(d, 2); for (i=1, 12, if (Palin(b), t=0; break); b=calcB(d)); if (t && Palin(b), write("b066133.txt", n++, " ", m); if (n==1000, return)) ) } [From Harry J. Smith, Feb 01 2010] CROSSREFS Sequence in context: A004607 A221008 A168153 * A119455 A168189 A045031 Adjacent sequences:  A066130 A066131 A066132 * A066134 A066135 A066136 KEYWORD base,nonn AUTHOR Klaus Brockhaus, Dec 08 2001 EXTENSIONS OFFSET changed from 0,1 to 1,1 by Harry J. Smith, Feb 01 2010 STATUS approved

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Last modified May 24 15:28 EDT 2013. Contains 225624 sequences.