A163648 -id:A163648 - cp's OEIS frontend

A230956 Semiprimes k with a semiprime number of syllables in their name in American English.

57, 74, 87, 106, 111, 121, 122, 123, 129, 133, 134, 141, 142, 143, 145, 146, 155, 158, 159, 161, 166, 169, 183, 185, 194, 201, 202, 203, 205, 206, 209, 217, 221, 226, 235, 249, 253, 254, 259, 262, 265, 289, 291, 295, 298, 299, 301, 302, 303, 305, 309

Offset: 1

Jonathan Vos Post, Nov 04 2013

This is to A163648 as semiprimes A001358 are to primes A000040.
The word "and" is excluded, 101 is "one hundred one" rather than "one hundred and one."
Number of syllables in n in American English is A075774.
See A231073 and A231075 for prime analogs counting words respectively letters.

			87 is in the sequence because 87 = 3 * 29 is semiprime, "eighty-seven" has 4 syllables, and 4 = 2^2 is also semiprime.
106 is in the sequence because 106 = 2 * 53 is semiprime and "one hundred six" has semiprime 4 syllables.
111 is in the sequence because 111 = 3 * 37 is semiprime and "one hundred eleven" has semiprime 6 = 2*3 syllables.

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Cf. A001358, A075774, A163648, A231073, A231075.

# uses function in A075774
from sympy import factorint
def issemiprime(n): return sum(factorint(n).values()) == 2
def ok(n): return issemiprime(A075774(n)) and issemiprime(n)
print([k for k in range(310) if ok(k)]) # Michael S. Branicky, May 27 2024

{k: k is in A001358 and A075774(k) is in A001358}.

Corrected and extended by Charles R Greathouse IV, Jan 23 2014

A231073 Primes whose English name has a prime number of words.

Original entry on oeis.org

23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 211, 307, 311, 313, 317, 401, 409, 419, 503, 509, 601, 607, 613, 617, 619, 701, 709, 719, 809, 811, 907, 911, 919, 1009, 1013, 1019, 1103, 1109, 1117, 1201, 1213, 1217, 1301, 1303, 1307, 1319, 1409

Offset: 1

M. F. Hasler, Nov 03 2013

Sequence A163648 is the analog considering syllables in the English name of p.

Index to OEIS: Sequences related to English words for the numbers

Cf. A231072, A163648.

forprime(p=1,1500,isprime(A231072(p))&&print1(p","))

A231075 Primes with a prime number of letters (A005589) in their (American) English name.

Original entry on oeis.org

2, 3, 7, 23, 37, 79, 83, 97, 101, 131, 149, 181, 191, 269, 281, 307, 337, 379, 383, 397, 419, 461, 541, 577, 601, 617, 631, 659, 691, 727, 733, 787, 797, 823, 827, 883, 887, 911, 919, 941, 977, 1013, 1019, 1051, 1061, 1129, 1151, 1153, 1163, 1171

Offset: 1

M. F. Hasler, Nov 03 2013

Spaces and hyphens don't count, as in A005589. See A163648 and A231073 for the analogs counting syllables resp. words.

Sequence A072686 is the British English analog, which in particular uses the additional "and": It features "one hundred and nine", but not "one hundred and one". In the present sequence, we do have "one hundred one" but not "one hundred nine".

Index entries for sequences related to number of letters in n

PARI
```
is(p)=isprime(A005589(p))&&isprime(p)
```

forprime(p=1,1200,isprime(A005589(p))&&print1(p","))

A164043 Numbers divisible by the number of syllables in their (American) English name.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 14, 16, 18, 20, 21, 24, 30, 33, 36, 39, 40, 42, 45, 48, 50, 51, 54, 60, 63, 66, 69, 72, 76, 80, 81, 84, 90, 93, 96, 99, 104, 108, 112, 115, 120, 126, 130, 132, 138, 140, 144, 147, 150, 156, 160, 162, 168, 175, 180, 186, 190, 192, 198

Offset: 1

Jonathan Vos Post, Aug 08 2009

The name has no extra "and" syllables, as in 104 being in this sequence because "one hundred four" has 4 syllables (which divides 104) rather than "one hundred and four" which has 5 syllables.

			a(15) = 21 because "twenty-one" has 3 syllables, and 3*7 = 21.

Index to OEIS: sequences related to English words for n

Cf. A075774, A045736, A002810 (British variant), A163648.

# uses function in A075774
def ok(n): return n and n%A075774(n) == 0
print([k for k in range(200) if ok(k)]) # Michael S. Branicky, May 27 2024

{k such that A075774(k)|k}.

84 inserted and more terms from Michael S. Branicky, May 27 2024

cp's OEIS Frontend

A230956 Semiprimes k with a semiprime number of syllables in their name in American English.

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A231073 Primes whose English name has a prime number of words.

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A231075 Primes with a prime number of letters (A005589) in their (American) English name.

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A164043 Numbers divisible by the number of syllables in their (American) English name.

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Keywords

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Programs

Python

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Extensions