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A075879 The (10^n)-th odd-digit number. 2
1, 19, 579, 13779, 397779, 11177779, 335777779, 7937777779, 179977777779, 5931777777779, 139757777777779, 5117377777777779, 113559777777777779, 3393517777777777779, 79991577777777777779, 1931953777777777777779, 59771197777777777777779, 1517537177777777777777779 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
a(n) = A014261(10^n). - Andrew Howroyd, Jan 17 2020
MAPLE
b:= proc(n) local m, r, d; m, r:= n, 0;
while m>0 do d:= irem(m, 5, 'm');
if d=0 then d:=5; m:= m-1 fi;
r:= d*2-1, r
od; parse(cat(r))/10
end:
a:= n-> b(10^n):
seq(a(n), n=0..20); # Alois P. Heinz, Jan 17 2020
MATHEMATICA
NextOddNbr[n_Integer] := Block[{d = IntegerDigits[n], c = 0, l}, l = Length[d] - 1; If[ OddQ[d[[ -1]]], d[[ -1]]++ ]; d[[ -1]]++; If[ d[[ -1]] > 10, c++; d[[ -1]] = 1]; While[l != 0, If[c == 1, d[[l]]++; c-- ]; If[ EvenQ[ d[[l]]], d[[l]]++ ]; If[ d[[l]] > 10, c++; d[[l]] = 1]; l-- ]; If[c == 1, d[[1]] = d[[1]] + 10]; FromDigits[d]]; k = 1; Do[k = Nest[NextOddNbr, k, 9*10^n]; Print[k], {n, 0, 7}]
PROG
(PARI) \\ here b(n) is A014261.
b(n)={my(k=1); while(n>5^k, n-=5^k; k++); fromdigits([2*d+1 | d<-digits(5^k+n-1, 5)]) - 3*10^k}
a(n)={b(10^n)} \\ Andrew Howroyd, Jan 17 2020
CROSSREFS
Sequence in context: A012845 A284111 A142023 * A287936 A226584 A180841
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Oct 16 2002
EXTENSIONS
Terms a(9) and beyond from Andrew Howroyd, Jan 17 2020
STATUS
approved

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Last modified July 15 18:49 EDT 2024. Contains 374333 sequences. (Running on oeis4.)