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A352328
Nonnegative numbers that are the sum of distinct Pell numbers (A000129).
0
0, 1, 2, 3, 5, 6, 7, 8, 12, 13, 14, 15, 17, 18, 19, 20, 29, 30, 31, 32, 34, 35, 36, 37, 41, 42, 43, 44, 46, 47, 48, 49, 70, 71, 72, 73, 75, 76, 77, 78, 82, 83, 84, 85, 87, 88, 89, 90, 99, 100, 101, 102, 104, 105, 106, 107, 111, 112, 113, 114, 116, 117, 118
OFFSET
0,3
COMMENTS
This sequence is the complement of A352323.
Although this is a list, it has offset 0 for mathematical reasons: indeed, so, the binary expansion of n encodes the positive Pell numbers summing to a(n).
Every nonnegative integer is the sum of two (not necessarily distinct) terms of this sequence.
LINKS
L. Carlitz, Richard Scoville, and V. E. Hoggatt, Jr., Pellian Representations, The Fibonacci Quarterly, Vol. 10, No. 5 (1972), pp. 449-488.
FORMULA
a(n) = Sum_{k >= 0} b_k * A000129(k+1) where Sum_{k >= 0} b_k * 2^k is the binary expansion of n.
A265744(a(n)) = A000120(n).
EXAMPLE
For n = 42:
- 42 = 2^5 + 2^3 + 2^1,
- so a(42) = A000129(5+1) + A000129(3+1) + A000129(1+1) = 70 + 12 + 2 = 84.
MATHEMATICA
With[{pell = LinearRecurrence[{2, 1}, {1, 2}, 7]}, Select[Union[Plus @@@ Subsets[pell]], # <= pell[[-1]] &]] (* Amiram Eldar, Mar 12 2022 *)
PROG
(PARI) a(n) = { my (v=0, k); while (n, n-=2^k=valuation(n, 2); v+=([2, 1; 1, 0]^(k+1))[2, 1]); return (v) }
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Mar 12 2022
STATUS
approved