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A193145
Self-composition of binary encoding of GF(2) polynomial.
0
0, 1, 2, 2, 16, 16, 18, 19, 512, 584, 674, 749, 912, 973, 770, 856, 65536, 65536, 65538, 65539, 65552, 65553, 65554, 65554, 69120, 69465, 68834, 69052, 68240, 68572, 67650, 67849, 33554432, 34603040, 35652098, 36700721, 37756944, 38805813, 39854162, 40903012, 42084864, 43138625, 44171426, 45225206, 46289296, 47334592, 48396610, 49441799, 52494336
OFFSET
0,3
EXAMPLE
7, 111 in base 2, is transformed to the polynomial x^2+x+1. Composing this with itself (mod 2) gives (x^2+x+1)^2 + (x^2+x+1) + 1 = x^4+x+1, which transforms back to 19; so a(7) = 19.
PROG
(PARI) tox(n) = local(x=Mod(1, 2)*X, xp=1, r); while(n>0, if(n%2, r+=xp); xp*=x; n\=2); r
a(n) = local(p); p=tox(n); subst(lift(subst(p, X, p)), X, 2)
CROSSREFS
Sequence in context: A093114 A016740 A353915 * A352348 A133922 A222954
KEYWORD
nonn
AUTHOR
STATUS
approved