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A036066
The summarize Lucas sequence: summarize the previous two terms, start with 1, 3.
4
1, 3, 1311, 2331, 331241, 14432231, 34433241, 54533231, 2544632221, 163534435221, 263544436231, 363554634231, 463554733221, 17364544733221, 37263554634231, 37363554734231, 37364544933221, 1937263554933221, 3927263544835231, 391827264534836231, 293827363544836231
OFFSET
0,2
COMMENTS
After the 26th term the sequence goes into a cycle of 46 terms.
"Summarize" uses here method C = A244112: in order of decreasing digit value.
FORMULA
a(n+1) = A244112(concat(a(n),a(n-1))). - M. F. Hasler, Feb 25 2018
MAPLE
a:= proc(n) option remember; `if`(n<2, 2*n+1, (p-> parse(cat(seq((c->
`if`(c=0, [][], [c, 9-i][]))(coeff(p, x, 9-i)), i=0..9))))(
add(x^i, i=map(x-> convert(x, base, 10)[], [a(n-1), a(n-2)]))))
end:
seq(a(n), n=0..20); # Alois P. Heinz, Jun 18 2022
MATHEMATICA
a[0] = 1; a[1] = 3; a[n_] := a[n] = FromDigits @ Flatten @ Reverse @ Select[ Transpose @ { DigitCount[a[n-1]] + DigitCount[a[n-2]], Append[ Range[9], 0]}, #[[1]] > 0 &];
Table[a[n], {n, 0, 17}] (* Jean-François Alcover, Dec 30 2017 *)
PROG
(PARI) {a=[1, 3]; for(n=1, 50, a=concat(a, A244112(eval(Str(a[n], a[n+1]))))); a} \\ M. F. Hasler, Feb 25 2018
CROSSREFS
Cf. A036059.
Cf. A244112 (summarizing as used here: by decreasing digit value), A047842 (alternative summarizing method: by increasing digit value), A047843 (another method: don't omit missing digits between smallest and largest one).
Sequence in context: A129078 A174826 A122389 * A262516 A060307 A119111
KEYWORD
base,easy,nice,nonn
STATUS
approved