cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-9 of 9 results.

A164790 a(n) is the smallest nonnegative number whose American English name has the letter "e" in the n-th position.

Original entry on oeis.org

8, 0, 1, 3, 3, 12, 13, 17, 21, 23, 23, 73, 101, 103, 103, 112, 113, 117, 121, 123, 123, 173, 323, 373, 1103, 1103, 1112, 1113, 1117, 1121, 1123, 1123, 1173, 1323, 1373, 3323, 3373, 11373, 13323, 13373, 17373, 23323, 23373, 73373, 101373, 103323, 103373, 111373
Offset: 1

Views

Author

Claudio Meller, Aug 26 2009

Keywords

Examples

			a(1)=8 ("Eight"), a(2)=0 ("zEro"), a(3)=1 ("onE"), a(4)=3 ("thrEe").

References

  • GCHQ, The GCHQ Puzzle Book, Penguin, 2016. See page 70.

Crossrefs

See A362120-A362122 for other versions.
Cf. A164789 ("o"), A164791 ("n"), A164792 ("t"), A164793 ("i"), A164794 ("f"), A164795 ("h"), A164796 ("r"), A164797 ("u").

Programs

  • Python
    from num2words import num2words
from itertools import count, islice
def n2w(n):
    return "".join(c for c in num2words(n).replace(" and ", "") if c.isalpha())
def A164790(n, t="e", i0=0): # t is target letter, i0 is start
    return next(i for i in count(i0) if len(w:=n2w(i))>=n and w[n-1]==t)
print([A164790(n) for n in range(1, 38)]) # Michael S. Branicky, Apr 21 2023
  • Python
    # faster for initial segment of sequence; uses n2w/imports above
def A164790gen(t="e", i0=0, offset=1): # generator of terms w
    adict, n = dict(), offset
    for i in count(i0):
        w = n2w(i)
        if t in w:
            locs = [i+1 for i, c in enumerate(w) if w[i] == t]
            for v in locs:
                if v not in adict: adict[v] = i
        while n in adict: yield adict[n]; n += 1
print(list(islice(A164790gen(), 50))) # Michael S. Branicky, Apr 21 2023

Extensions

a(25) and beyond from Michael S. Branicky, Mar 25 2021
Name edited by N. J. A. Sloane, Apr 20 2023

A164789 a(n) is the smallest number which has in its English name the letter "o" in the n-th position, or -1 if no such number exists.

Original entry on oeis.org

1, 4, 2, 0, 4000000000000000000000000000, 41, 21, 24, 22, 72, 101, 104, 102, 304, 302, 141, 121, 124, 122, 172, 322, 372, 1104, 1102, 1304, 1302, 1141, 1121, 1124, 1122, 1172, 1322, 1372, 3322, 3372, 11372, 13322, 13372, 17372, 23322, 23372, 73372, 101372, 103322, 103372
Offset: 1

Views

Author

Claudio Meller, Aug 26 2009

Keywords

Examples

			a(1)=1 ("One"), a(2)=4 ("fOur"), a(3)=2 ("twO"), a(4)=0 ("zerO"), a(5)=4*10^27 ("fourOctillion").

Crossrefs

Cf. A164790 ("e"), A164791 ("n"), A164792 ("t"), A164793 ("i").
Cf. A164794 ("f"), A164795 ("h"), A164796 ("r"), A164797 ("u").

Extensions

a(5) corrected and a(23) and beyond from Michael S. Branicky, Mar 25 2021

A164792 a(n) is the smallest number whose English name has the letter "t" in the n-th position, or -1 if no such number exists.

Original entry on oeis.org

2, -1, -1, 15, 8, 17, 22, 72, 13000, 48, 28, 78, 302, 115, 108, 117, 122, 172, 322, 148, 128, 178, 328, 378, 1115, 1108, 1117, 1122, 1172, 1322, 1148, 1128, 1178, 1328, 1378, 3328, 3378, 11378, 13328, 13378, 17378, 23328, 23378, 73378, 101378, 103328, 103378
Offset: 1

Views

Author

Claudio Meller, Aug 26 2009

Keywords

Examples

			a(1)=2 ("Two"), a(4)=15 ("fifTeen"), a(9)=13000 ("thirteenThousand"), a(13)=302 ("threehundredTwo").

Crossrefs

Cf. A164789 ("o"), A164790 ("e"), A164791 ("n"), A164793 ("i").
Cf. A164794 ("f"), A164795 ("h"), A164796 ("r"), A164797 ("u").

Extensions

a(9) corrected, and a(25) and beyond from Michael S. Branicky, Feb 02 2021

A164793 a(n) is the smallest number whose English name has the letter "i" in the n-th position, or -1 if no such number exists.

Original entry on oeis.org

-1, 5, 13, -1, 1000000, 4000000, 45, 25, 75, 13000000, 17000000, 105, 113, 305, 313, 3013, 145, 125, 175, 325, 375, 3075, 1105, 1113, 1305, 1313, 3305, 1145, 1125, 1175, 1325, 1375, 3325, 3375, 11375, 13325, 13375, 17375, 23325, 23375, 73375, 101375, 103325
Offset: 1

Views

Author

Claudio Meller, Aug 26 2009

Keywords

Comments

Original definition used "-2 for infinite".

Examples

			a(2)=5 ("fIve"), a(3)=13 ("thIrteen"), a(5)=10^6 ("onemIllion").

Crossrefs

Cf. A164789 ("o"), A164790 ("e"), A164791 ("n"), A164792 ("t").
Cf. A164794 ("f"), A164795 ("h"), A164796 ("r"), A164797 ("u").

Extensions

a(11) and beyond from Michael S. Branicky, Feb 02 2021
Name changed to remove "-2" (see Comments), and a(1) and a(4) changed from -2 to -1 by Jon E. Schoenfield, Feb 02 2021

A164794 a(n) is the smallest number whose English name has the letter "f" in the n-th position, or -1 if no such number exists.

Original entry on oeis.org

4, -1, 15, -1, -1, 44, 24, 74, -1, -1, 104, 404, 115, 415, 315, 144, 124, 174, 324, 374, 3074, 1104, 1404, 1115, 1415, 1315, 1144, 1124, 1174, 1324, 1374, 3324, 3374, 11374, 13324, 13374, 17374, 23324, 23374, 73374, 101374, 103324, 103374, 111374, 113324
Offset: 1

Views

Author

Claudio Meller, Aug 26 2009

Keywords

Examples

			a(1)=4 ("Four"), a(3)=15 ("fiFteen"), a(11)=104 ("onehundredFour").

Crossrefs

Cf. A164789 ("o"), A164790 ("e"), A164791 ("n"), A164792 ("t").
Cf. A164793 ("i"), A164795 ("h"), A164796 ("r"), A164797 ("u").

Extensions

a(21) and beyond from Michael S. Branicky, Feb 02 2021

A164795 a(n) is the smallest number whose English name has the letter "h" in the n-th position, or -1 if no such number exists.

Original entry on oeis.org

-1, 3, -1, 8, 400, 300, 43, 23, 48, 28, 78, 103, 403, 108, 408, 308, 143, 123, 148, 128, 178, 328, 378, 1403, 1108, 1408, 1308, 1143, 1123, 1148, 1128, 1178, 1328, 1378, 3328, 3378, 11378, 13328, 13378, 17378, 23328, 23378, 73378, 101378, 103328, 103378
Offset: 1

Views

Author

Claudio Meller, Aug 26 2009

Keywords

Examples

			a(2)=3 ("tHree"), a(4)=8 ("eigHt"), a(12)=103 ("onehundredtHree").

Crossrefs

Cf. A164789 ("o"), A164790 ("e"), A164791 ("n"), A164792 ("t").
Cf. A164793 ("i"), A164794 ("f"), A164796 ("r"), A164797 ("u").

Extensions

a(24) and beyond from Michael S. Branicky, Feb 02 2021

A164796 a(n) is the smallest number whose English name has the letter "r" in the n-th position, or -1 if no such number exists.

Original entry on oeis.org

-1, -1, 0, 4, 1000000000000, 4000000000000, 3000000000000, 43, 23, 24, 74, 24000000000000, 103, 104, 303, 304, 3004, 143, 123, 124, 174, 324, 374, 1103, 1104, 1303, 1304, 3303, 1143, 1123, 1124, 1174, 1324, 1374, 3324, 3374, 11374, 13324, 13374, 17374, 23324
Offset: 1

Views

Author

Claudio Meller, Aug 26 2009

Keywords

Examples

			a(3)=0 ("zeRo"), a(4)=4 ("fouR"), a(5)=1000000000000 ("onetRillion"), a(13)=103 ("onehundredthRee").

Crossrefs

Cf. A164789 ("o"), A164790 ("e"), A164791 ("n"), A164792 ("t").
Cf. A164793 ("i"), A164794 ("f"), A164795 ("h"), A164797 ("u").

Extensions

a(24) and beyond from Michael S. Branicky, Feb 02 2021

A164797 a(n) is the smallest number whose English name has the letter "u" in the n-th position, or -1 if no such number exists.

Original entry on oeis.org

-1, -1, 4, 1000000000000000000000000000000000000, 100, 400, 300, 44, 24, 74, 15000, 13000, 104, 404, 304, 4004, 1100, 144, 124, 174, 324, 374, 3024, 3074, 1104, 1404, 3404, 3304, 1144, 1124, 1174, 1324, 1374, 3324, 3374, 11374, 13324, 13374, 17374, 23324, 23374
Offset: 1

Views

Author

Claudio Meller, Aug 26 2009

Keywords

Examples

			a(3)=4 ("foUr"), a(5)=100 ("onehUndred"), a(4)=10^36 ("oneUndecillion").

Links

Crossrefs

Cf. A164789 ("o"), A164790 ("e"), A164791 ("n"), A164792 ("t").
Cf. A164793 ("i"), A164794 ("f"), A164795 ("h"), A164796 ("r").

Extensions

a(4) corrected, and a(27) and beyond from Michael S. Branicky, Feb 02 2021

A173204 a(n) is the smallest number which has in its English name the letter "n" in the n-th position beginning the count from the end.

Original entry on oeis.org

7, 1, 20, 9, 17, 19, 24, 19, 91, 94, 93, 101, 104, 103, 111, 115, 113, 117, 124, 123, 173, 923, 973, 1101, 1104, 1103, 1111, 1115, 1113, 1117, 1124, 1123, 1173, 1323, 1373, 9323, 9373, 17373, 19173, 19323, 19373, 91373, 93323
Offset: 1

Views

Author

Claudio Meller, Feb 12 2010

Keywords

Examples

			a(1) = seveN, a(2) = oNe, a(3) = tweNty, a(4)= Nine, a(5) = seveNteen, etc.

Crossrefs

Cf. A164791 ("n" in n-th position),.
Cf. A173203 (similar for "e"), A173206 (similar for "t").

Programs

  • Mathematica
    ePos[n_] := Flatten@Position[DeleteCases[Reverse@Characters@IntegerName[n, "Words"], a_ /; MemberQ[{" ", "\[Hyphen]"}, a]], "n"]; t = {}; i = 1; Monitor[Table[Do[If[MemberQ[ePos[i], n], Return[lst = AppendTo[t, i]; i = 1; lst], i++], \[Infinity]], {n, 1, 43, 1}] // Last, {ProgressIndicator[n, {1, 43}], n, i}] (* Robert P. P. McKone, Feb 07 2022 *)

Extensions

More terms from Robert P. P. McKone, Feb 08 2022
Showing 1-9 of 9 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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