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A065208
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Three 'Reverse and Add' steps are needed to reach a palindrome.
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3
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59, 68, 86, 95, 155, 156, 157, 158, 164, 165, 168, 178, 180, 184, 185, 186, 194, 199, 249, 254, 255, 256, 257, 263, 264, 267, 277, 283, 284, 285, 293, 298, 299, 348, 349, 354, 355, 356, 362, 366, 376, 382, 384, 389, 392, 397, 398, 399, 439, 447, 448, 449, 452, 453, 455, 461, 462, 465, 475, 481, 482, 483, 488, 489, 491, 496, 497, 498, 499, 538, 546, 547, 548, 551, 552, 553, 554, 560, 561, 564, 574, 580, 581, 582, 587, 588, 590, 596, 597, 598, 637, 645, 647, 650, 651, 652, 653, 660, 663, 673, 680, 681, 687, 694, 695, 697, 736, 744, 745, 746, 750
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The number of steps starts at 0, so palindromes (cf. A002113) are excluded.
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,1000
Index entries for sequences related to Reverse and Add!
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MATHEMATICA
| palQ[n_]:=Module[{idn=IntegerDigits[n]}, idn==Reverse[idn]]
tst[n_]:=palQ/@NestList[#+FromDigits[Reverse[IntegerDigits[#]]]&, n, 3]=={False, False, False, True}
Select[Range[750], tst]
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PROG
| (ARIBAS): revadd_steps(3, 54). For the definition of function revadd_steps see A065206.
(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, 3, if (Palin(p), b=0; break); p=Rev(p) + p); if (b && Palin(p), write("b065208.txt", n++, " ", m); if (n==1000, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 14 2009]
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CROSSREFS
| A002113, A015979, A065206.
Sequence in context: A087766 A096339 A015979 * A061759 A061764 A162000
Adjacent sequences: A065205 A065206 A065207 * A065209 A065210 A065211
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KEYWORD
| nonn,base
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AUTHOR
| Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Oct 21 2001
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EXTENSIONS
| OFFSET changed from 0,1 to 1,1 by Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 14 2009
Additional terms provided and Mathematica program provided by Harvey P. Dale, Nov. 26, 2010
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