A143617 Where record values occur in A010371.

0, 8, 10, 18, 20, 28, 68, 88, 108, 188, 200, 208, 288, 688, 888, 1088, 1888, 2008, 2088, 2888, 6888, 8888, 10888, 18888, 20088, 20888, 28888, 68888, 88888, 108888, 188888, 200888, 208888, 288888, 688888, 888888, 1088888, 1888888, 2008888, 2088888

Offset

1,2

Comments

a(n) is the least number using n + 6 (or n + 5 for n < 5) segments on a 7-segment display, when '6' uses 6 segments. This is essentially the same as A038619 (starts with 1, 2, 6 instead of 0) and A216261 (= a(n) uses n segments: has 4 values before 0 and 22 before 20). - M. F. Hasler, Jun 17 2020

Links

Table of n, a(n) for n=1..40.

Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,0,10,-10).

Formula

a(n+7) = 10*a(n) + 8 for n > 4.

A010371(a(n)) = A143616(n) and A010371(m) < A143616(n) for m < a(n).

A010371(a(n)) = n + 6 for n > 4. - M. F. Hasler, Jun 23 2020

a(n) = a(n-1) + 10*a(n-7) - 10*a(n-8). - Wesley Ivan Hurt, Jul 03 2020

Mathematica

Block[{f, s}, MapIndexed[(f[#2[[1]] - 1] = #1) &, {6, 2, 5, 5, 4, 5, 6, 4, 7, 6}]; s = Array[Total[f /@ IntegerDigits[#]] &, 10^6, 0]; Map[-1 + FirstPosition[s, #][[1]] &, Union@ FoldList[Max, s]]] (* Michael De Vlieger, Jun 23 2020 *)

Prog

(PARI) apply( {A143617(n)=if(n>11, self()(n-7)*10+8, n>9, 12*n+68, n>6, 20*n-72, n*5-2-n%2*3)}, [1..55]) \\ M. F. Hasler, Jun 23 2020

Crossrefs

Cf. A010371, A143616.

Sequence in context: A374622 A287270 A299988 * A015732 A179474 A373727

Adjacent sequences: A143614 A143615 A143616 * A143618 A143619 A143620

Keyword

nonn

Author

Reinhard Zumkeller, Aug 27 2008

Status

approved