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A022471 Length of n-th term of A022470. 2
1, 2, 4, 4, 6, 10, 12, 14, 22, 26, 30, 44, 56, 70, 98, 130, 162, 216, 292, 358, 470, 628, 792, 1050, 1384, 1788, 2334, 3072, 3974, 5162, 6784, 8786, 11420, 14992, 19484, 25388, 33160, 43262, 56252, 73392, 95798, 124496, 162556, 212048, 275976, 360154 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) is the length of the n-th term of many sequences generated by methods A and B, including those shown here:

Method A, 1st term ... Method B, 1st term

A001155, 0

A006751, 2 ......... A022470, 2

A006715, 3 ......... A022499, 3

A001140, 4 ......... A022500, 4

A001141, 5 ......... A022501, 5

A001143, 6 ......... A022502, 6

A001145, 7 ......... A022503, 7

A001151, 8 ......... A022504, 8

A001154, 9 ......... A022505, 9

Clark Kimberling, Jun 14 2013

LINKS

Peter J. C. Moses, Table of n, a(n) for n = 1..3000

MATHEMATICA

a[0] = 2; a[n_] := a[n] = FromDigits[Flatten[{First[#], Length[#]} & /@ Split[IntegerDigits[a[n - 1]]]]]; Map[Length[IntegerDigits[a[#]]] &, Range[0, 40]] (* Peter J. C. Moses, Jun 14 2013 *)

p = {9, -9, 6, -16, 5, 2, 0, -9, -1, -1, 20, 2, 6, -3, -15, -13, 15, 20, 15, -26, -28, 7, 6, 26, -27, -4, 9, -15, 3, 2, 8, 43, 9, -39, -24, -2, -24, 28, 9, 13, 13, -18, -12, -16, 14, 13, 16, 8, -36, 1, -6, -8, 15, 1, 14, 3, -6, -7, -3, 2, -2, 2, 2, 0, -1, -2, -1, 3, 3, -1, -1, -1}; q = {-6, 9, -9, 18, -16, 11, -14, 8, -1, 5, -7, -2, -8, 14, 5, 5, -19, -3, 6, 7, 6, -16, 7, -8, 22, -17, 12, -7, -5, -7, 8, -4, 7, 9, -13, 4, 6, -14, 14, -19, 7, 13, -2, 4, -18, 0, 1, 4, 12, -8, 5, 0, -8, -1, -7, 8, 5, 2, -3, -3, 0, 0, 0, 0, 2, 1, 0, -3, -1, 1, 1, 1, -1}; gf = Fold[x #1 + #2 &, 0, p]/Fold[x #1 + #2 &, 0, q]; CoefficientList[Series[gf, {x, 0, 100}], x] (* Peter J. C. Moses, Jun 16 2013 *)

CROSSREFS

Cf. A022470.

Sequence in context: A237828 A340626 A351489 * A359294 A224487 A185342

Adjacent sequences: A022468 A022469 A022470 * A022472 A022473 A022474

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified February 2 03:19 EST 2023. Contains 359997 sequences. (Running on oeis4.)