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1, 0, 15, 110, 605, 3100, 15595, 78090, 390585, 1953080, 9765575, 48828070, 244140565, 1220703060, 6103515555, 30517578050, 152587890545, 762939453040, 3814697265535, 19073486328030, 95367431640525, 476837158203020, 2384185791015515, 11920928955078010, 59604644775390505, 298023223876953000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| Digit sum = digit product = 5^n.
Numbers a(n)=k such that number m with k 5's and n 1's has digit product=digit sum.
One of the infinite series of numbers with digit product = digit sum. Cf. A107583, A107584.
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index to sequences with linear recurrences with constant coefficients, signature (7,-11,5)
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FORMULA
| a(n) = 7*a(n-1)-11*a(n-2)+5*a(n-3), n>=3. - Vincenzo Librandi, Oct 26 2011
G.f. ( -1-26*x^2+7*x ) / ( (5*x-1)*(x-1)^2 ). - R. J. Mathar, Oct 26 2011
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MATHEMATICA
| Table[5^m-5*m, {m, 0, 10}]
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PROG
| (MAGMA)[(5^n - 5*n): n in [0..25]][From Vincenzo Librandi, Dec 16 2010]
(PARI) a(n)=5^n-5*n \\ Charles R Greathouse IV, Oct 26 2011
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CROSSREFS
| Cf. A107583, A107584.
Sequence in context: A205352 A055504 A060931 * A205347 A054367 A199225
Adjacent sequences: A107582 A107583 A107584 * A107586 A107587 A107588
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KEYWORD
| nonn,easy
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AUTHOR
| Zak Seidov (zakseidov(AT)yahoo.com), May 16 2005
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