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 1-4 of 4 results.

A099807 If a,b are prime numbers satisfying the Diophantine equation a^3+b^3=c^2, then a is -1 mod 12 and b is 1 mod 12, or vice versa. Choose 'b' to be 1 mod 12. This is the sequence of 'b' values, sorted by the magnitude of c.

Original entry on oeis.org

37, 2137, 8929, 1801, 48817, 6637, 57241, 133597, 151477, 334717, 3889, 127717, 786697, 735781, 1154017, 38557, 1662229, 2446777, 3882661, 3811669, 2747449, 3716701, 5634637, 3600097, 9836221, 10591849, 7139569, 9473161, 11395309
Offset: 0

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Author

James R. Buddenhagen, Oct 26 2004

Keywords

Comments

All terms of this sequence are of the form -3*M^4+N^4+6*M^2*N^2 for some pair M,N of relatively prime positive integers of opposite parity. For each n, a=A099806[n], b=A099807[n] are prime numbers and a^3 + b^3 = c^2, for some integer c. c is divisible by 12 and A098970 gives the values of c/12.

Examples

			37 is in the sequence because 37 is a prime congruent to 1 mod 12 and 11^3+37^3=228^2.
		

Crossrefs

A099808 If a,b are primes which satisfy the Diophantine equation a^3 + b^3 = c^2, then this sequence consists of the numbers sqrt((a+b)/48), sorted by the magnitude of c.

Original entry on oeis.org

1, 15, 28, 35, 44, 44, 55, 56, 91, 90, 88, 119, 161, 165, 200, 184, 273, 319, 285, 357, 377, 400, 380, 434, 550, 517, 592, 615, 638, 667, 682, 666, 740, 697, 784, 688, 825, 682, 846, 770, 893, 814, 868, 925, 775, 899, 885, 1007, 1045, 1040, 1078, 1184, 1015
Offset: 0

Views

Author

James R. Buddenhagen, Oct 26 2004

Keywords

Comments

For each n let a=A099806(n), b=A099807(n). Then sqrt((a+b)/48) is an integer and equals A099808(n). Note that a^3 + b^3 = c^2 factors as (a+b)*(a^2-a*b+b^2). The first factor (a+b) is 48*d^2, some d. This sequence tabulates the d values. Remember, a and b are prime numbers.

Examples

			From 11^3 + 37^3 = 228^2 we get sqrt((a+b)/48) = (11+37)/48 = 1, so 1 is in the sequence. [corrected by _Harvey P. Dale_, Apr 12 2011]
		

Crossrefs

A099806 If a,b are prime numbers satisfying the Diophantine equation a^3+b^3=c^2, then a is -1 mod 12 and b is 1 mod 12, or vice versa. Choose 'a' to be -1 mod 12. This is the sequence of 'a' values, sorted by the magnitude of c.

Original entry on oeis.org

11, 8663, 28703, 56999, 44111, 86291, 87959, 16931, 246011, 54083, 367823, 552011, 457511, 571019, 765983, 1586531, 1915163, 2437751, 16139, 2305883, 4074743, 3963299, 1296563, 5440991, 4683779, 2238023, 9682703, 8681639, 8142803
Offset: 0

Views

Author

James R. Buddenhagen, Oct 26 2004

Keywords

Comments

All terms of this sequence are of the form 3*M^4-N^4+6*M^2*N^2 for some pair M,N of relatively prime positive integers of opposite parity.

Examples

			11 is in the sequence because 11 is -1 mod 12 and 11^3+37^3 = 228^2.
		

Crossrefs

A099809 Let a,b be prime numbers satisfying the Diophantine equation a^3+b^3=(a+b)*(a^2-a*b+b^2)=c^2. Then the second factor a^2-a*b+b^2 is 3*e^2 for some integer e. This sequence tabulates the 'e' values, sorted by magnitude of c.

Original entry on oeis.org

19, 4513, 14689, 32401, 26929, 48019, 44641, 72739, 124099, 179683, 211249, 288979, 395089, 386131, 587233, 905059, 1040419, 1410049, 2237011, 1919779, 2078209, 2220451, 2950963, 2767489, 4919971, 5582449, 5019889, 5255761
Offset: 0

Views

Author

James R. Buddenhagen, Oct 26 2004

Keywords

Comments

For each n let a=A099806[n], b=A099807[n], c/12=A098970. Then a^3+b^3=c^2. The left side factors as (a+b)*(a^2-a*b+b^2). The second factor is 3*e^2 for some integer e. The sequence tabluates the 'e' values. These 'e' values all have the form 3*M^4+N^4, for some pair M,N of relatively prime integers of opposite parity. Remember, a and b are prime numbers.

Examples

			11^3+37^3=228^2, 11^2-11*37+37^2=3*e^2 with e=19, so 19 is in the sequence.
		

Crossrefs

Showing 1-4 of 4 results.