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 1-5 of 5 results.

A167844 Convex primes.

Original entry on oeis.org

101, 103, 107, 109, 113, 127, 137, 139, 149, 211, 223, 227, 229, 239, 307, 311, 313, 317, 337, 347, 349, 359, 401, 409, 419, 421, 433, 439, 449, 457, 503, 509, 521, 523, 547, 557, 569, 601, 607, 613, 617, 619, 631, 643, 647, 659, 701, 709, 719, 727, 733, 739
Offset: 1

Views

Author

Omar E. Pol, Nov 13 2009

Keywords

Comments

Primes in A135641.
Primes whose structure of digits represents a convex function or a convex object. In the graphic representation the points are connected by imaginary line segments from left to right.
See A246033 for a different notion of "convex prime". - N. J. A. Sloane, Jul 25 2017

Links

Crossrefs

Cf. A134811, A134951, A134971, A135641, A167841, A167842, A167843, A167845, A167846, A167853.
See also A246033.

Programs

  • PARI
    \\ See Links section.

Extensions

More terms from Rémy Sigrist, Dec 15 2018

A167843 Obtuse-angled primes.

Original entry on oeis.org

113, 127, 137, 139, 149, 157, 167, 179, 199, 211, 223, 227, 229, 233, 239, 257, 269, 277, 311, 331, 337, 347, 349, 359, 367, 379, 389, 421, 431, 433, 443, 449, 457, 467, 479, 499, 521, 541, 557, 569, 577, 599, 631, 641, 643, 653, 661, 677, 733, 743, 751, 761
Offset: 1

Views

Author

Omar E. Pol, Nov 13 2009

Keywords

Comments

Primes in A135603.
Primes whose structure of digits represents an obtuse angle. The vertex is an internal digit. In the graphic representation the points are connected by imaginary line segments from left to right.

Links

Crossrefs

Cf. A134811, A134951, A134971, A135603, A167841, A167842, A167844, A167845, A167846, A167853.

Programs

  • Python
    # uses agen() from A135603
from sympy import isprime
g = filter(isprime, agen())
print([next(g) for n in range(1, 53)]) # Michael S. Branicky, Aug 03 2022

Extensions

a(12) and beyond from Michael S. Branicky, Aug 03 2022

A167845 Concave primes.

Original entry on oeis.org

131, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 233, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 331, 353, 367, 373, 379, 383, 389, 397, 431, 443, 461, 463, 467, 479, 487, 491, 499, 541, 563, 571, 577, 587, 593, 599, 641, 653, 661, 673
Offset: 1

Views

Author

Omar E. Pol, Nov 13 2009

Keywords

Comments

Primes in A135642.
Primes whose structure of digits represents a concave function or a concave object. In the graphic representation the points are connected by imaginary line segments from left to right.

Crossrefs

Cf. A134811, A134951, A134971, A135642, A167841, A167842, A167843, A167844, A167846, A167853.

Extensions

More terms from Max Alekseyev, Apr 24 2010

A167846 Concave-convex primes.

Original entry on oeis.org

1021, 1031, 1033, 1051, 1061, 1063, 1069, 1087, 1091, 1093, 1097, 1103, 1109, 1151, 1153, 1163, 1171, 1181, 1187, 1193, 1201, 1213, 1217, 1223, 1229, 1277, 1279, 1283, 1289, 1291, 1297, 1301, 1303, 1307, 1319, 1327, 1361, 1367, 1373, 1381, 1399, 1409, 1423
Offset: 1

Views

Author

Omar E. Pol, Nov 13 2009

Keywords

Comments

Primes in A163278.
Prime numbers with more than three digits that are not straight-line numbers (A135643), concave numbers (A135642) or convex numbers (A135641).

Links

Crossrefs

Cf. A134811, A134951, A134971, A135641, A135642, A135643, A163278, A167841, A167842, A167843, A167844, A167845, A167853.

Extensions

More terms from Rémy Sigrist, May 22 2019

A167847 Straight-line primes.

Original entry on oeis.org

11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 4567, 76543, 23456789, 1111111111111111111, 11111111111111111111111
Offset: 1

Views

Author

Omar E. Pol, Nov 14 2009

Keywords

Comments

Prime numbers with 2 digits together with the primes whose digits are in arithmetic progression. The structure of digits represents a straight line.
Note that in the graphic representation the points are connected by imaginary line segments (see also A135643).
Note that all two-digit primes are straight-line primes but this sequence has no three-digit terms.
No further terms between 23456789 and 115507867=prime(6600000). - R. J. Mathar, Dec 04 2009
All terms after 23456789 are repunit primes (A004022) with number of digits: 19, 23, 317, 1031, 49081, 86453, 109297, 270343, ... (A004023). - Jens Kruse Andersen, Jul 21 2014

Examples

			The number 4567 is straight-line prime:
  . . . .
  . . . .
  . . . 7
  . . 6 .
  . 5 . .
  4 . . .
  . . . .
  . . . .
  . . . .
  . . . .

Crossrefs

Cf. A000040, A004022, A004023, A134811, A134951, A134971, A135643, A167841, A167842, A167843, A167844, A167845, A167846, A167853.

Extensions

2 more terms from R. J. Mathar, Dec 04 2009
a(25)-a(26) from Jens Kruse Andersen, Jul 21 2014
Showing 1-5 of 5 results.

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