A271559 a(n) = G_n(12), where G is the Goodstein function defined in A266201.

12, 107, 1065, 15685, 280019, 5764910, 134217867, 3486784574, 100000000211, 3138428376974, 106993205379371, 3937376385699637, 155568095557812625, 6568408355712891083, 295147905179352826375, 14063084452067724991593, 708235345355337676358285, 37589973457545958193356327

Offset

0,1

Comments

Goodstein's theorem shows that such sequence converges to zero for any starting value.

Links

Nicholas Matteo, Table of n, a(n) for n = 0..383

R. L. Goodstein, On the Restricted Ordinal Theorem, The Journal of Symbolic Logic 9, no. 2 (1944), 33-41.

Example

G_1(12) = B_2(12)-1 = B_2(2^(2+1)+2^2)-1 = 3^(3+1)+3^3-1 = 107;
G_2(12) = B_3(3^(3+1)+2*3^2+2*3+2)-1 = 4^(4+1)+2*4^2+2*4+2-1 = 1065;
G_3(12) = B_4(4^(4+1)+2*4^2+2*4+1)-1 = 5^(5+1)+2*5^2+2*5+1-1 = 15685;
G_4(12) = B_5(5^(5+1)+2*5^2+2*5)-1 = 6^(6+1)+2*6^2+2*6-1 = 280019;
G_5(12) = B_6(6^(6+1)+2*6^2+6+5)-1 = 7^(7+1)+2*7^2+7+5-1 = 5764910;
G_6(12) = B_7(7^(7+1)+2*7^2+7+4)-1 = 8^(8+1)+2*8^2+8+4-1 = 134217867;
G_7(12) = B_8(8^(8+1)+2*8^2+8+3)-1 = 9^(9+1)+2*9^2+9+3-1 = 3486784574.

Prog

(PARI) lista(nn) = {print1(a = 12, ", "); for (n=2, nn, pd = Pol(digits(a, n)); q = sum(k=0, poldegree(pd), if (c=polcoeff(pd, k), c*x^subst(Pol(digits(k, n)), x, n+1), 0)); a = subst(q, x, n+1) - 1; print1(a, ", "); ); }

Crossrefs

Cf. A056193: G_n(4), A059933: G_n(16), A211378: G_n(19), A215409: G_n(3), A222117: G_n(15), A266204: G_n(5), A266205: G_n(6), A271554: G_n(7), A271555: G_n(8), A271556: G_n(9), A271557: G_n(10), A271558: G_n(11), A266201: G_n(n).

Sequence in context: A218111 A166755 A230712 * A154671 A321672 A241230

Adjacent sequences: A271556 A271557 A271558 * A271560 A271561 A271562

Keyword

nonn,fini

Author

Natan Arie Consigli, Apr 11 2016

Status

approved