A362271 Contribution to the OEIS

 

A362271 a(1) = 1, then add, subtract and multiply 2, 3, 4; 5, 6, 7; ... in that order. 6

1, 3, 0, 0, 5, -1, -7, 1, -8, -80, -69, -81, -1053, -1039, -1054, -16864, -16847, -16865, -320435, -320415, -320436, -7049592, -7049569, -7049593, -176239825, -176239799, -176239826, -4934715128, -4934715099, -4934715129, -152976168999, -152976168967, -152976169000 (list; graph; refs; listen; history; edit; text; internal format)

OFFSET 1,2 LINKS Table of n, a(n) for n=1..33. FORMULA a(1)=1; for n > 1, a(n) = a(n-1) + n if n mod 3 = 2, a(n-1) - n if n mod 3 = 0, a(n-1) * n if n mod 3 = 1. EXAMPLE a(2) = 1 + 2 = 3; a(3) = 3 - 3 = 0; a(4) = 0 * 4 = 0. MATHEMATICA FoldList[If[Mod[#2, 3]==2, #1+#2, If[Mod[#2, 3]==0, #1-#2, #1*#2]]&, 1, Range[2, 33]] (* James C. McMahon, Oct 09 2023 *) PROG (Python) from itertools import count, islice def A362271_gen(): # generator of terms yield (a:=1) for n in count(2, 3): yield (a:=a+n) yield (a:=a-n-1) yield (a:=a*(n+2)) A362271_list = list(islice(A362271_gen(), 20)) # Chai Wah Wu, Apr 19 2023 CROSSREFS Other operation orders: A077382, A077383, A362269, A362270, A362272. Sequence in context: A092669 A255986 A011400 * A115013 A072736 A135090 Adjacent sequences: A362268 A362269 A362270 * A362272 A362273 A362274 KEYWORD sign AUTHOR James C. McMahon, Apr 13 2023 STATUS approved