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A051846 Digits 1..n in strict descending order n..1 interpreted in base n+1. 7
1, 7, 57, 586, 7465, 114381, 2054353, 42374116, 987654321, 25678050355, 736867805641, 23136292864686, 789018236134297, 29043982525261081, 1147797409030816545, 48471109094902544776, 2178347851919531492065 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

All odd-indexed (2n+1) terms are divisible by (2n+1). See A051847.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..200

FORMULA

a(n) = Sum_{i=1..n} i*(n+1)^(i-1).

a(n) = ((n+1)^(n+1)*(n-1) + 1)/n^2 = A062806(n+1)/(n+1) - (n+1)^(n+1). - Benoit Cloitre, Sep 28 2002

a(n) = A023811(n+1)*A028310(n-1) + A199969(n+1). - M. F. Hasler, Jan 22 2013

EXAMPLE

a(1) = 1, a(2) = 2*3 + 1 = 7, a(3) = 3*(4^2) + 2*4 + 1 = 57, a(4) = 4*(5^3) + 3*(5^2) + 2*5 + 1 = 586.

MAPLE

a(n) := proc(n) local i; add(i*((n+1)^(i-1)), i=1..n); end;

PROG

(PARI) a(n)=((n+1)^(n+1)*(n-1)+1)/n^2

(Maxima) makelist(((n+1)^(n+1)*(n-1) + 1)/n^2, n, 1, 20); /* Martin Ettl, Jan 25 2013 */

CROSSREFS

The right edge of A051845. Cf. also A023811.

Sequence in context: A176733 A062192 A122649 * A231540 A316442 A289876

Adjacent sequences:  A051843 A051844 A051845 * A051847 A051848 A051849

KEYWORD

easy,base,nonn

AUTHOR

Antti Karttunen, Dec 13 1999

EXTENSIONS

Minor edits in formulas by M. F. Hasler, Oct 11 2019

STATUS

approved

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Last modified January 29 10:34 EST 2020. Contains 331337 sequences. (Running on oeis4.)