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 A007091 Numbers in base 5. (Formerly M0595) 56
 0, 1, 2, 3, 4, 10, 11, 12, 13, 14, 20, 21, 22, 23, 24, 30, 31, 32, 33, 34, 40, 41, 42, 43, 44, 100, 101, 102, 103, 104, 110, 111, 112, 113, 114, 120, 121, 122, 123, 124, 130, 131, 132, 133, 134, 140, 141, 142, 143, 144, 200, 201, 202, 203, 204, 210, 211, 212, 213, 214, 220, 221, 222, 223, 224, 230 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS From Rick L. Shepherd, Jun 25 2009: (Start) Nonnegative integers with no decimal digit > 4. Thus nonnegative integers in base 10 whose doubling by normal addition or multiplication requires no carry operation. (End) It appears that this sequence corresponds to the numbers n for which twice the sum of digits of n is the sum of digits of 2*n. - Rémy Sigrist, Nov 22 2009 REFERENCES N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Nathaniel Johnston, Table of n, a(n) for n = 0..10000 R. G. Wilson, V, Letter to N. J. A. Sloane, Sep. 1992 FORMULA a(0)=0 a(n)=10*a(n/5) if n==0 (mod 5) a(n)=a(n-1)+1 otherwise. - Benoit Cloitre, Dec 22 2002 a(n) = n + 1/2*Sum_{k >= 1} 10^k*floor(n/5^k). Cf. A037454, A037462 and A102491. - Peter Bala, Dec 01 2016 MAPLE A007091 := proc(n) local l: if(n=0)then return 0: fi: l:=convert(n, base, 5): return op(convert(l, base, 10, 10^nops(l))): end: seq(A007091(n), n=0..58); # Nathaniel Johnston, May 06 2011 MATHEMATICA Table[ FromDigits[ IntegerDigits[n, 5]], {n, 0, 60}] PROG (PARI) a(n)=if(n<1, 0, if(n%5, a(n-1)+1, 10*a(n/5))) (PARI) apply( A007091(n)=fromdigits(digits(n, 5)), [0..66]) \\ M. F. Hasler, Nov 18 2019 CROSSREFS Cf. A000042 (base 1), A007088 (base 2), A007089 (base 3), A007090 (base 4), A007092 (base 6), A007093 (base 7), A007094 (base 8), A007095 (base 9). Cf. A037454, A037462, A102491. Sequence in context: A037325 A293292 A037469 * A058185 A080897 A117383 Adjacent sequences:  A007088 A007089 A007090 * A007092 A007093 A007094 KEYWORD nonn,easy,base AUTHOR STATUS approved

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Last modified December 15 11:43 EST 2019. Contains 329999 sequences. (Running on oeis4.)