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A306106
Numbers with digits in {0,1,2,3} such that every other digit is strictly less than its neighbors.
6
0, 1, 2, 3, 10, 20, 21, 30, 31, 32, 101, 102, 103, 201, 202, 203, 212, 213, 301, 302, 303, 312, 313, 323, 1010, 1020, 1021, 1030, 1031, 1032, 2010, 2020, 2021, 2030, 2031, 2032, 2120, 2121, 2130, 2131, 2132, 3010, 3020, 3021, 3030, 3031, 3032, 3120, 3121, 3130, 3131, 3132, 3230, 3231, 3232, 10101, 10102, 10103
OFFSET
1,3
COMMENTS
Terms of A032859 written in base 4.
FORMULA
a(n) = A007090(A032859(n)).
Terms in A297147 having only digits < 4; intersection of A297147 and A007090.
PROG
(PARI) A(Nmax=100, K=3, A=[0..K], i=vector(2*K, i, max(1, i-K+1)), c(T, v)=apply(t->t+T, v))={for(n=0, oo, for(k=10, K*11, if(k%10<k\10, k%10|| i=concat(i, 1+#A); A=concat(A, c(k*10^n, A[i[K*n+k%10+1]..i[K*n+K+1]-1])); #A<Nmax||return(A))))}
CROSSREFS
Cf. A306105 .. A306111 and A297147: analog for bases 3..9 and 10.
Cf. A032859 and A032858 .. A032865 for other bases 3..10.
Sequence in context: A122822 A295951 A083944 * A165550 A328780 A184261
KEYWORD
nonn,base
AUTHOR
M. F. Hasler, Oct 05 2018
STATUS
approved