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.

A165492 Primes p where the digital sum of p^2 is equal to 13.

Original entry on oeis.org

7, 29, 47, 61, 79, 151, 349, 389, 461, 601, 1051, 1249, 1429, 1451, 1789, 2239, 3499, 4799, 5011, 5101, 5501, 5749, 10501, 11149, 14249, 50101, 51001, 55001, 100501, 100649, 101149, 150001, 318751, 448999, 501001, 1009951, 5000011, 5000101, 5001001, 50000101
Offset: 1

Views

Author

Vincenzo Librandi, Sep 21 2009

Keywords

Examples

			29 is in the sequence because 29^2 = 841 and 8+4+1 = 13.
1789 is in the sequence because 1789^2 = 3200521 and 3+2+0+0+5+2+1 = 13.

Links

Crossrefs

Cf. A165502 - A165504.

Programs

  • Magma
    [p: p in PrimesUpTo(5*10^7) | &+Intseq(p^2) eq 13]; // Vincenzo Librandi, Sep 26 2015
  • Mathematica
    Select[Prime[Range[80000]],Total[IntegerDigits[#^2]]==13&]  (* Harvey P. Dale, Apr 08 2011 *)

Formula

{A000040(i) : A123157(i) = 13}. [R. J. Mathar, Sep 29 2009]

Extensions

More terms from R. J. Mathar, Sep 29 2009
a(37)-a(40) from Hiroaki Yamanouchi, Sep 23 2014

A165504 Primes p with a digits sum of p^2 equal to 43.

Original entry on oeis.org

887, 1697, 1723, 1867, 1913, 2083, 2137, 2417, 2543, 2633, 2687, 2767, 2803, 2957, 3083, 3109, 3137, 3433, 3793, 3847, 3947, 4073, 4217, 4423, 4567, 4657, 4783, 4793, 4937, 5099, 5233, 5279, 5333, 5387, 5431, 5647, 5683, 5827, 6043, 6053, 6133, 6143
Offset: 1

Views

Author

Vincenzo Librandi, Sep 21 2009

Keywords

Examples

			887 is in the sequence because 887^2=786769 and 7+8+6+7+6+9=43.
1723 is in the sequence because 1723^2=2968729 and 2+9+6+8+7+2+9=43.

Links

Crossrefs

Cf. primes p where the digital sum of p^2 is equal to: A226803 (7), A165492 (13), A165493 (19), A165502 (31), A165503 (37), this sequence (43).

Programs

  • Magma
    [p: p in PrimesUpTo(6150) | &+Intseq(p^2) eq 43]; // Vincenzo Librandi, Sep 12 2013
  • Mathematica
    Select[Prime[Range[300]], Total[IntegerDigits[#^2]] == 43&] (* Vincenzo Librandi, Sep 12 2013 *)

Formula

{A000040(i) : A123157(i) = 43} [R. J. Mathar, Sep 29 2009]

Extensions

More terms from R. J. Mathar, Sep 29 2009

A165503 Primes p with a digits sum of p^2 equal to 37.

Original entry on oeis.org

433, 613, 683, 773, 827, 863, 1063, 1117, 1187, 1223, 1567, 1583, 1657, 1693, 1783, 1907, 1997, 2017, 2087, 2141, 2143, 2161, 2267, 2357, 2393, 2467, 2557, 2593, 2609, 2663, 2719, 2753, 2789, 2843, 2879, 2897, 2969, 2971, 3023, 3041, 3061, 3167, 3187
Offset: 1

Views

Author

Vincenzo Librandi, Sep 21 2009

Keywords

Examples

			433 is in the sequence because 433^2=187489 and 1+8+7+4+8+9=37.
1783 is in the sequence because 1783^2=3179089 and 3+1+7+9+0+8+9=37.

Links

Crossrefs

Cf. primes p where the digital sum of p^2 is equal to: A226803 (7), A165492 (13), A165493 (19), A165502 (31), this sequence (37), A165504 (43).

Programs

  • Magma
    [p: p in PrimesUpTo(6150) | &+Intseq(p^2) eq 37]; // Vincenzo Librandi, Sep 12 2013
  • Mathematica
    Select[Prime[Range[500]], Total[IntegerDigits[#^2]]== 37&] (* Vincenzo Librandi, Sep 12 2013 *)

Formula

{A000040(i) : A123157(i) = 37} [R. J. Mathar, Sep 29 2009]

Extensions

More terms from R. J. Mathar, Sep 29 2009

A229058 Primes p where the digital sum of p^2 is equal to 25.

Original entry on oeis.org

67, 113, 157, 193, 257, 283, 311, 337, 373, 409, 419, 463, 509, 599, 643, 653, 661, 743, 761, 769, 797, 1013, 1031, 1039, 1103, 1129, 1193, 1237, 1301, 1381, 1399, 1427, 1471, 1481, 1553, 1571, 1579, 1597, 1733, 1759, 1823, 1831, 1877, 2029, 2039, 2111, 2129
Offset: 1

Views

Author

Vincenzo Librandi, Sep 12 2013

Keywords

Comments

From Bruno Berselli, Sep 12 2013: (Start)
Primes q such that the digital sum of q^2 is 1 < k < 50:
k | q
---|------------
4 | 2, 11, 101;
7 | A226803;
9 | 3;
10 | A226802;
13 | A165492;
16 | A165459;
19 | A165493;
22 | 43, 97, 191, 227, 241, 317, 331, 353, ... ;
25 | this sequence;
28 | 163, 197, 233, 307, 359, 397, 431, 467, ... ;
31 | A165502;
34 | 167, 293, 383, 563, 607, 617, 733, 787, ... ;
37 | A165504;
40 | 313, 947, 983, 1303, 1483, 1609, 1663, ... ;
43 | A165504;
46 | 883, 937, 1367, 1637, 2213, 2447, 2683, ... ;
49 | 1667, 2383, 2437, 2617, 2963, 4219, 4457, ... . (End)

Links

Crossrefs

Cf. A165459, A165492, A165493, A165502-A165504, A226802, A226803.

Programs

  • Magma
    [p: p in PrimesUpTo(2600) | &+Intseq(p^2) eq 25];
  • Mathematica
    Select[Prime[Range[400]], Total[IntegerDigits[#^2]] == 25 &]

A234429 Numbers which are the digital sum of the square of some prime.

Original entry on oeis.org

4, 7, 9, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49, 52, 55, 58, 61, 64, 67, 70, 73, 76, 79, 82, 85, 88, 91, 94, 97, 100, 103, 106, 109, 112, 115, 118, 121, 124, 127, 130, 133, 136, 139, 142, 145, 148, 151, 154, 157, 160, 163, 166, 169, 172, 175, 178
Offset: 1

Views

Author

Antonio Graciá Llorente, Dec 26 2013

Keywords

Comments

A123157 sorted and duplicates removed.

Crossrefs

Cf. A067180, A067523, A123157, A056991.
Cf. A062397, A226803, A226802, A165492, A165459 A165493, A229058, A165502, A165503, A165504.

Programs

  • PARI
    terms(nn) = {v = []; forprime (p = 1, nn, v = concat(v, sumdigits(p^2));); vecsort(v,,8);} \\ Michel Marcus, Jan 08 2014

Formula

From Robert G. Wilson v, Sep 28 2014: (Start)
Except for 3, all primes are congruent to +-1 (mod 3). Therefore, (3n +- 1)^2 = 9n^2 +- 6n + 1 which is congruent to 1 (mod 3).
4: 2, 11, 101, ... (A062397);
7: 5, 149, 1049, ... (A226803);
9: only 3;
10: 19, 71, 179, 251, 449, 20249, 24499, 100549, ... (A226802);
13: 7, 29, 47, 61, 79, 151, 349, 389, 461, 601, 1051, 1249, 1429, ... (A165492);
16: 13, 23, 31, 41, 59, 103, 131, 139, 211, 229, 239, 347, 401, ... (A165459);
19: 17, 37, 53, 73, 89, 107, 109, 127, 181, 199, 269, 271, 379, ... (A165493);
22: 43, 97, 191, 227, 241, 317, 331, 353, 421, 439, 479, 569, 619, 641, ...;
25: 67, 113, 157, 193, 257, 283, 311, 337, 373, 409, 419, 463, ... (A229058);
28: 163, 197, 233, 307, 359, 397, 431, 467, 487, 523, 541, 577, 593, 631, ...;
31: 83, 137, 173, 223, 263, 277, 281, 367, 443, 457, 547, 587, ... (A165502);
34: 167, 293, 383, 563, 607, 617, 733, 787, 823, 859, 877, 941, 967, 977, ...;
37: 433, 613, 683, 773, 827, 863, 1063, 1117, 1187, 1223, 1567, ... (A165503);
40: 313, 947, 983, 1303, 1483, 1609, 1663, 1933, 1973, 1987, 2063, 2113, ...;
43: 887, 1697, 1723, 1867, 1913, 2083, 2137, 2417, 2543, 2633, ... (A165504);
46: 883, 937, 1367, 1637, 2213, 2447, 2683, 2791, 2917, 3313, 3583, 3833, ...;
49: 1667, 2383, 2437, 2617, 2963, 4219, 4457, 5087, 5281, 6113, 6163, ...;
... Also see A229058. (End)
Conjectures from Chai Wah Wu, Apr 16 2025: (Start)
a(n) = 2*a(n-1) - a(n-2) for n > 5.
G.f.: x*(2*x^4 - x^3 - x^2 - x + 4)/(x - 1)^2. (End)

Extensions

a(36) from Michel Marcus, Jan 08 2014
a(37)-a(54) from Robert G. Wilson v, Sep 28 2014
More terms from Giovanni Resta, Aug 15 2019
Showing 1-5 of 5 results.

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

Content is available under The OEIS End-User License Agreement.