A065217 Numbers from which 12 'Reverse and Add' steps are needed to reach a palindrome.

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

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

Index entries for sequences related to Reverse and Add!

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