login
A378254
Cogrowth sequence of the 20-element group C10 X C2 = <S,T | S^10, T^2, [S,T]>.
2
1, 1, 1, 1, 1, 2, 67, 1002, 8009, 43759, 184758, 646878, 1971883, 5541966, 16231216, 60090032, 290305577, 1523150157, 7564006759, 34099637859, 139541849878, 526321168143, 1878476551128, 6603812572941, 24052434515891, 94278969044262, 396750746960712
OFFSET
0,6
COMMENTS
Gives the even terms, all the odd terms are 0.
FORMULA
G.f.: (10*x^9+75*x^8+162*x^7-48*x^6+127*x^5-126*x^4+84*x^3-36*x^2+9*x-1) / ((4*x-1) * (25*x^4+10*x^2-5*x+1) * (x^4+4*x^3+6*x^2-x+1)).
CROSSREFS
Cf. A377840 (C8 X C2), A377627 (C6 X C2), A078789 (D10).
Sequence in context: A046848 A318064 A089661 * A355326 A191808 A364069
KEYWORD
nonn,easy
AUTHOR
Sean A. Irvine, Nov 20 2024
STATUS
approved