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 A135210 Numbers n such that Sum_digits(n) + Sum_digits(n+1) = Sum_digits(2*n+1). 3
 0, 1, 2, 3, 4, 9, 10, 11, 12, 13, 14, 19, 20, 21, 22, 23, 24, 29, 30, 31, 32, 33, 34, 39, 40, 41, 42, 43, 44, 49, 99, 100, 101, 102, 103, 104, 109, 110, 111, 112, 113, 114, 119, 120, 121, 122, 123, 124, 129, 130, 131, 132, 133, 134, 139, 140, 141, 142, 143, 144, 149 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS G. C. Greubel, Table of n, a(n) for n = 1..2000 EXAMPLE n=19 -> Sum_digits(19)=10; Sum_digits(20)=2 -> 10+2=12; Sum_digits(19+20)=12 MAPLE P:=proc(n) local a, b, i, k, w, y, x; for i from 0 by 1 to n do w:=0; k:=i; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; x:=0; k:=i+1; while k>0 do x:=x+k-(trunc(k/10)*10); k:=trunc(k/10); od; y:=0; k:=2*i+1; while k>0 do y:=y+k-(trunc(k/10)*10); k:=trunc(k/10); od; if w+x=y then print(i); fi; od; end: P(1000); MATHEMATICA Select[Range[0, 1000], Total[IntegerDigits[#]] + Total[IntegerDigits[# + 1]] == Total[IntegerDigits[2*# + 1]] &] (* G. C. Greubel, Oct 01 2016 *) PROG (PARI) is(n)=my(s=sumdigits, t); t=s(2*n+1)-s(n); t>0 && t==s(n+1) \\ Charles R Greathouse IV, Oct 01 2016 CROSSREFS Cf. A127273. Sequence in context: A113234 A316534 A140238 * A037468 A265746 A047454 Adjacent sequences:  A135207 A135208 A135209 * A135211 A135212 A135213 KEYWORD easy,nonn,base AUTHOR Paolo P. Lava and Giorgio Balzarotti, Dec 18 2007 STATUS approved

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Last modified April 8 08:54 EDT 2020. Contains 333313 sequences. (Running on oeis4.)