A057268 - OEIS

A057268

a(n-1)+k=a(n) => a(n)*k=a(n+1).

1, 3, 6, 18, 216, 42768, 1819863936, 3311826913612597248, 10968197499701667312529793029329125376, 120301356392461906290006219878693096559247086148184247242087281541542576128

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OFFSET

0,2

COMMENTS

For +k and ^k see A057269. (Using *k and ^k gives another formulation of A014222. In this case the sequence could start 1,2 - see A014221.)

See the Comments section in A001696 as a connection to some sieving process. - Ctibor O. Zizka, Feb 13 2025

LINKS

Table of n, a(n) for n=0..9.

FORMULA

a(0) = 1, a(1) = 3, for n >= 2, a(n) = a(n - 1)*(a(n - 1) - a(n - 2)). - Ctibor O. Zizka, Feb 13 2025

MATHEMATICA

nxt[{a_, b_}]:={b, b(b-a)}; NestList[nxt, {1, 3}, 9][[All, 1]] (* Harvey P. Dale, Sep 05 2017 *)

CROSSREFS

Cf. A001696, A057269.

Sequence in context: A345134 A135504 A307334 * A085401 A085061 A294570

Adjacent sequences: A057265 A057266 A057267 * A057269 A057270 A057271

KEYWORD

easy,nonn

AUTHOR

Jonas Wallgren, Aug 22 2000

EXTENSIONS

More terms from Harvey P. Dale, Sep 05 2017

STATUS

approved