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 A066122 In base 2, one 'Reverse and Add' step is needed to reach a palindrome. 12
 2, 4, 6, 8, 10, 12, 14, 16, 18, 24, 30, 32, 34, 36, 38, 40, 42, 48, 52, 56, 62, 64, 66, 68, 70, 80, 82, 96, 100, 102, 112, 114, 126, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148, 150, 160, 162, 168, 170, 176, 178, 192, 196, 198, 200, 204, 208, 212, 224 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The analog of A065206 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 (ARIBAS): function b2revadd_steps(k, stop: integer); var c, n, m, steps, rev: integer; begin n := 0; c := 0; while c < stop do m := n; rev := b2reverse(m); steps := 0; while steps < k and m <> rev do m := m + rev; rev := b2reverse(m); inc(steps); end; if steps = k and m = rev then write(n, " "); inc(c); end; inc(n); end; end; b2revadd_steps(1, 66). (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) } { n=0; for (m=1, 10^9, b=baseE(m, 2); r=Rev(b); d=baseI(r, 2) + m; b=baseE(d, 2); if (Palin(b), write("b066122.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Feb 01 2010 CROSSREFS Cf. A006995, A065206. Sequence in context: A118070 A276128 A152966 * A119766 A030143 A110725 Adjacent sequences:  A066119 A066120 A066121 * A066123 A066124 A066125 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 August 17 15:28 EDT 2018. Contains 313816 sequences. (Running on oeis4.)