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A082430 a(1)=1; for n > 1, a(n) = n*(a(n-1) + a(n-2) + ... + a(2) + a(1)) + 4. 0
1, 6, 25, 132, 824, 5932, 48444, 442916, 4484524, 49828044, 602919332, 7892762164, 111156400476, 1675896499484, 26934050884564, 459674468429892, 8302870086014924, 158242935756990316, 3173649989348528004 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

More generally, if m is an integer and a(1)=1, a(n) = n*(a(n-1) + a(n-2) + ... + a(2) + a(1)) + m then a(n) has a closed form formula as a(n) = floor/ceiling(n*r(m)*n!) where r(m) = frac(e*m) + 0 or + 1/2 or -1/2 + integer. (See Example section.)

LINKS

Table of n, a(n) for n=1..19.

FORMULA

For n >= 2, a(n) = ceiling(n*(19/2 - 4*e)*n!).

EXAMPLE

r(10) = frac(10*e) + 1/2 + 2;

r(12) = frac(12*e) - 1/2 + 3;

r(15) = frac(15*e) + 3;

r(18) = frac(18*e) - 1/2 + 4.

CROSSREFS

Cf. A007808, A074143.

Sequence in context: A073967 A188207 A275541 * A136593 A012293 A012594

Adjacent sequences:  A082427 A082428 A082429 * A082431 A082432 A082433

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Apr 24 2003

STATUS

approved

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Last modified July 8 01:48 EDT 2020. Contains 335502 sequences. (Running on oeis4.)