A282637 -id:A282637

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Search: a282637 -id:a282637

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A282636

a(1) = 1. a(n) is the smallest natural number such that a(n) > a(n-1), the name of a(n) in (American) English ends with the letter a(n-1) starts with, and a(n) makes the sequence extendable.

+10
1

1, 2, 8, 9, 10, 28, 38, 88, 89, 91, 97, 107, 122, 132, 142, 152, 162, 172, 182, 192, 202, 208, 228, 238, 248, 258, 268, 278, 288, 298, 308, 328, 338, 348, 358, 368, 378, 388, 398, 808, 809, 812, 821, 823, 825, 829, 831, 833, 835, 839, 841, 843, 845, 849, 851, 853, 855, 859

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

"a(n) makes the sequence extendable" means the name of a(n) does not start with any of the letters f and s.

LINKS

Table of n, a(n) for n=1..58.

EXAMPLE

38 is followed by 88 as 48, 58, 68 and 78 cannot make the sequence extendable.

MATHEMATICA

names = StringReplace[

IntegerName /@ Range[1000], {"\[Hyphen]" -> "", " " -> ""}];

lst = {1}; next[n_] := next[n] =

Module[{pos = Last[lst] + 1},

While[

Or[

And[First[Characters[names[[Last[lst]]]]] !=

Last[Characters[names[[pos]]]], pos <= Length[names]],

MemberQ[{"f", "s"}, First[Characters[names[[pos]]]]] == True

pos++

];

AppendTo[lst, pos]

];

seq[n_] := Nest[next, 1, n]; seq[57]

CROSSREFS

Cf. A277971, A277972, A281067, A281068, A282637.

KEYWORD

easy,nonn,word

AUTHOR

Ivan N. Ianakiev, Feb 20 2017

STATUS

approved

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