A099968 Second column of triangle in A099964.

1, 2, 3, 6, 14, 31, 78, 235, 665, 1926, 5886, 21832, 75333, 266377, 933842, 3422282, 14954936, 61055379, 254751651, 1054728818, 4378056288, 18699691530, 94021272519, 443332334411, 2132051480643, 10181045388314, 48729093879838

Offset: 1

Author

N. J. A. Sloane, Nov 13 2004

Keywords

• nonn
• easy

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..750

Crossrefs

Cf. A099964, A099965, A099966.

Programs

Haskell

a099968 = flip a099964 1 -- Reinhard Zumkeller, May 02 2012

Maple

with(linalg):rev:=proc(a) local n, p; n:=vectdim(a): p:=i->a[n+1-i]: vector(n,p) end: ps:=proc(a) local n, q; n:=vectdim(a): q:=i->sum(a[j],j=1..i): vector(n,q) end: pss:=proc(a) local n, q; n:=vectdim(a): q:=proc(i) if i<=n then sum(a[j],j=1..i) else sum(a[j],j=1..n) fi end: vector(n+1,q) end: tr:={seq(n*(n+1)/2,n=1..30)}: R[0]:=vector(1,1): for n from 1 to 30 do if member(n,tr)=false then R[n]:=ps(rev(R[n-1])) else R[n]:=pss(rev(R[n-1])) fi od: seq(R[n][2],n=1..30); # Emeric Deutsch, Nov 16 2004

Extensions

More terms from Emeric Deutsch, Nov 16 2004

Offset corrected by Reinhard Zumkeller, May 02 2012