A266204 a(n) = G_n(5), where G_n(k) is the Goodstein function defined in A266201.
5, 27, 255, 467, 775, 1197, 1751, 2454, 3325, 4382, 5643, 7126, 8849, 10830, 13087, 15637, 18499, 21691, 25231, 29137, 33427, 38119, 43231, 48781, 54787, 61267, 68239, 75721, 83731, 92287, 101407, 111108, 121409, 132328, 143883, 156092, 168973, 182544, 196823
Offset: 0
Examples
G_0(5) = 5; G_1(5) = B_2(5) - 1 = B_2(2^2 + 1) - 1 = 27; G_2(5) = B_3(3^3) - 1 = 4^4 - 1 = 255; G_3(5) = B_4(3*4^3 + 3*4^2 + 3*4 + 3) - 1 = 3*5^3 + 3*5^2 + 3*5 + 3 - 1 = 467.
Links
- Nicholas Matteo, Table of n, a(n) for n = 0..10000
- R. L. Goodstein, On the Restricted Ordinal Theorem, The Journal of Symbolic Logic 9, no. 2 (1944), 33-41.
- Wikipedia, Goodstein sequence
Crossrefs
Programs
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PARI
bump(a, n) = {if (a < n, return (a)); my(pd = Pol(digits(a, n))); my(de = vector(poldegree(pd)+1, k, k--; polcoeff(pd, k))); my(bde = vector(#de, k, k--; bump(k, n))); my(q = sum(k=0, poldegree(pd), if (c=polcoeff(pd, k), c*x^bde[k+1], 0))); return(subst(q, x, n+1)); } lista(nn) = {print1(a = 5, ", "); for (n=2, nn, a = bump(a, n)-1; print1(a, ", "); ); } \\ Michel Marcus, Feb 28 2016
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