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A254398
Final digits of A237424 in decimal representation.
2
1, 4, 7, 4, 7, 7, 4, 7, 7, 7, 4, 7, 7, 7, 7, 4, 7, 7, 7, 7, 7, 4, 7, 7, 7, 7, 7, 7, 4, 7, 7, 7, 7, 7, 7, 7, 4, 7, 7, 7, 7, 7, 7, 7, 7, 4, 7, 7, 7, 7, 7, 7, 7, 7, 7, 4, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 4, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 4, 7, 7, 7, 7, 7, 7, 7
OFFSET
1,2
COMMENTS
a(n) = A237424(n) mod 10;
n with a(n) = 4: A237424(n) = (10^a+10^b+1)/3 with b = 0, see also A093137, A133384;
n with a(n) = 7: A237424(n) = (10^a+10^b+1)/3 with 0 < b <= a;
length of k-th run of consecutive 7s = k;
digits 0, 2, 3, 5, 6, 8 and 9 do not occur.
PROG
(Haskell)
a254398 = flip mod 10 . a237424
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Feb 23 2015
STATUS
approved