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 A261675 Minimal number of palindromes in base 10 that add to n. 12
 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 1, 2, 1, 2, 2, 2, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,11 COMMENTS This sequence coincides with A088601 for n <= 301, but differs at n=302. Although A088601 and this sequence agree for a large number of terms, because of their importance they warrant separate entries. Cilleruelo and Luca prove that a(n) <= 3 (in fact they prove this for any fixed base g>=5). - Danny Rorabaugh, Feb 26 2016 LINKS N. J. A. Sloane, Table of n, a(n) for n = 0..10000 Javier Cilleruelo and Florian Luca, Every positive integer is a sum of three palindromes, arXiv preprint arXiv:1602.06208 [math.NT], 2016. William D. Banks, Every natural number is the sum of forty-nine palindromes, INTEGERS 17 (2016), 9 pp. James Grime and Brady Haran, Every Number is the Sum of Three Palindromes (2018), Numberphile video PROG (PARI) ispal(n)=my(d=digits(n)); d==Vecrev(d); a(n)=my(L=n\2, d, e); if(ispal(n), return(1)); d=[1]; while((e=fromdigits(d))<=L, if(ispal(n-e), return(2)); my(k=#d, i=(k+1)\2); while(i&&d[i]==9, d[i]=0; d[k+1-i]=0; i--); if(i, d[i]++; d[k+1-i]=d[i], d=vector(#d+1); d[1]=d[#d]=1)); 3; \\ Charles R Greathouse IV, Nov 12 2018 CROSSREFS Cf. A002113, A035137, A088601, A260255, A261422. Sequence in context: A163376 A261913 A088601 * A028950 A094916 A036485 Adjacent sequences:  A261672 A261673 A261674 * A261676 A261677 A261678 KEYWORD nonn,base AUTHOR N. J. A. Sloane, Sep 02 2015 STATUS approved

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Last modified September 23 09:03 EDT 2020. Contains 337298 sequences. (Running on oeis4.)