A082458 - OEIS

A082458

Multiply by 1, add 1, multiply by 2, add 2, etc., starting with 0.

0, 0, 1, 2, 4, 12, 15, 60, 64, 320, 325, 1950, 1956, 13692, 13699, 109592, 109600, 986400, 986409, 9864090, 9864100, 108505100, 108505111, 1302061332, 1302061344, 16926797472, 16926797485, 236975164790, 236975164804, 3554627472060, 3554627472075, 56874039553200, 56874039553216

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,4

COMMENTS

Bisections: A007526 and A038154.

LINKS

Paolo Xausa, Table of n, a(n) for n = 0..800

FORMULA

For n>=2, a(2n)=floor(e*n!)-1, a(2*n+1)=(n+1)*(floor(e*n!)-1). - Benoit Cloitre, Apr 28 2003

MATHEMATICA

Module[{a = 0}, Join[{a}, Flatten[Array[{a *= #, a += #} &, 20]]]] (* Paolo Xausa, Oct 24 2024 *)

PROG

(PARI) a(n)=if(n<2, 0, if(n%2, (n+1)/2*(floor(exp(1)*((n-1)/2)!)-1), floor(exp(1)*(n/2)!)-1))

(PARI) A082458(n, a=0)={for(i=2, n+1, if(bittest(i, 0), a+=i\2, a*=i\2)); a} \\ M. F. Hasler, Feb 25 2018

CROSSREFS

Cf. A019464 (same, but start with 1), A019465 (start with 2), A019466 (start with 3).

Cf. A019460 .. A019463 & A082448 (similar, but first add, then multiply).

Sequence in context: A106135 A067268 A285378 * A230770 A224703 A171943

Adjacent sequences: A082455 A082456 A082457 * A082459 A082460 A082461

KEYWORD

nonn,changed

AUTHOR

Vladeta Jovovic, Apr 25 2003

EXTENSIONS

Edited by M. F. Hasler, Feb 25 2018

STATUS

approved