A277972 a(1) = 1. a(n) is the smallest unlisted number, the name of which contains the first letter of the name of a(n-1) in English.

1, 2, 3, 8, 5, 4, 14, 15, 24, 10, 12, 13, 16, 6, 7, 17, 26, 18, 9, 11, 19, 20, 21, 22, 23, 25, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 64, 60, 61, 62, 63, 65, 66, 67, 68, 69

Offset

1,2

Links

Table of n, a(n) for n=1..69.

Mathematica

name[n_]:=IntegerName[n, "Words"]; a[1]=1;
a[n_]:=a[n]=Module[{i=1}, While[Or[MemberQ[Table[a[k], {k, 1, n-1}], i],
!StringContainsQ[name[i], StringTake[name[a[n-1]], 1]]], i++ ]; i];
a/@Range[69] (* Ivan N. Ianakiev, Dec 20 2021 *)

Crossrefs

Cf. A277971.

Sequence in context: A192646 A338841 A100208 * A222243 A264978 A268675

Adjacent sequences: A277969 A277970 A277971 * A277973 A277974 A277975

Keyword

easy,nonn,word

Author

Ivan N. Ianakiev, Nov 07 2016

Status

approved