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 A065217 Numbers from which 12 'Reverse and Add' steps are needed to reach a palindrome. 3
 2069, 2159, 2249, 2339, 2429, 2519, 2609, 2699, 2789, 2879, 2969, 3068, 3158, 3248, 3338, 3428, 3518, 3608, 3698, 3788, 3878, 3968, 4067, 4157, 4247, 4337, 4427, 4517, 4607, 4697, 4787, 4877, 4967, 5066, 5156, 5246, 5336, 5426, 5516, 5606, 5696, 5786 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The number of steps starts at 0, so palindromes (cf. A002113) are excluded. This sequence coincides with the corresponding sequence not excluding palindromes (A015993) for the entries shown in the database. The first divergence occurs at 10901. 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); 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) } { n=0; for (m = 0, 10^9, p=m; b=1; for (i=1, 12, if (Palin(p), b=0; break); p=Rev(p) + p); if (b && Palin(p), write("b065217.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Oct 14 2009 CROSSREFS Cf. A002113, A015993, A065206. Sequence in context: A168432 A256744 A015993 * A249288 A200829 A035871 Adjacent sequences:  A065214 A065215 A065216 * A065218 A065219 A065220 KEYWORD nonn,base AUTHOR Klaus Brockhaus, Oct 21 2001 EXTENSIONS Offset changed from 0 to 1 by Harry J. Smith, Oct 14 2009 STATUS approved

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Last modified May 15 04:03 EDT 2021. Contains 343909 sequences. (Running on oeis4.)