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 1-3 of 3 results.

A154786 Row sums of triangle in A154725.

Original entry on oeis.org

0, 0, 0, 8, 10, 12, 14, 32, 36, 40, 44, 72, 52, 56, 90, 64, 102, 144, 38, 120, 168, 132, 138, 240, 200, 156, 270, 168, 174, 360, 124, 320, 396, 136, 350, 432, 296, 380, 546, 320, 328, 672, 344, 352, 810, 368, 376, 672, 294, 600, 816, 520, 530, 864, 660, 784, 1140
Offset: 1

Views

Author

Omar E. Pol, Jan 15 2009, Jan 16 2009

Keywords

Crossrefs

Cf. A154724, A154725, A154726, A154727, A154783, A154784, A154785.
Cf. A005843, A061357, A154720, A154787. - Omar E. Pol, Jan 20 2009

Programs

  • Maple
    A154786 := proc(n) local a,d; a := 0 ; for d from 1 to n-2 do if isprime(n-d) and isprime(n+d) then a := a+2*n; fi; od: a ; end: for n from 1 to 80 do printf("%d,",A154786(n)) ; od: # R. J. Mathar, Jan 18 2009

Formula

a(n) = A154785(n) - n.
a(n) = A005843(n)*A061357(n). - Omar E. Pol, Jan 20 2009

Extensions

Edited by Omar E. Pol, Jan 17 2009
Extended by R. J. Mathar, Jan 18 2009

A154784 Row sums of triangle in A154721.

Original entry on oeis.org

0, 4, 6, 16, 10, 24, 28, 32, 54, 60, 44, 96, 52, 56, 120, 96, 102, 144, 76, 120, 210, 176, 138, 288, 200, 156, 324, 168, 174, 420, 186, 320, 396, 204, 350, 504, 370, 380, 546, 400, 328, 756, 344, 352, 900, 368, 376, 672, 392, 600
Offset: 1

Views

Author

Omar E. Pol, Jan 15 2009

Keywords

Comments

a(n) is even for all n.

Links

Crossrefs

Cf. A154720, A154721, A154723, A154783, A154785, A154786.

Programs

  • Maple
    isnotcomp:=proc(n)return (n=1 or isprime(n)) end:
for n from 1 to 50 do rsum:=0: for k from 1 to 2*n-1 do if(not k=n and (isnotcomp(k) and isnotcomp(2*n-k)))then rsum:=rsum+k:fi:od: printf("%d, ",rsum):od: # Nathaniel Johnston, Apr 19 2011

Formula

a(n) = A154783(n) - n.

Extensions

Edited by Omar E. Pol, Jan 17 2009
a(11)-a(50) from Nathaniel Johnston, Apr 19 2011

A154785 Row sums of triangle in A154724.

Original entry on oeis.org

1, 2, 3, 12, 15, 18, 21, 40, 45, 50, 55, 84, 65, 70, 105, 80, 119, 162, 57, 140, 189, 154, 161, 264, 225, 182, 297, 196, 203, 390, 155, 352, 429, 170, 385, 468, 333, 418, 585, 360, 369, 714, 387, 396, 855, 414, 423, 720, 343, 650
Offset: 1

Views

Author

Omar E. Pol, Jan 15 2009

Keywords

Comments

Also, row sums of triangle in A154726.

Links

Crossrefs

Cf. A154724, A154725, A154726, A154727, A154783, A154784, A154786.

Programs

  • Maple
    for n from 1 to 50 do rsum:=0: for k from 1 to 2*n-1 do if(k=n or (isprime(k) and isprime(2*n-k)))then rsum:=rsum+k:fi:od: printf("%d, ",rsum):od: # Nathaniel Johnston, Apr 19 2011

Formula

a(n) = A154786(n) + n.

Extensions

a(11)-a(50) from Nathaniel Johnston, Apr 19 2011
Showing 1-3 of 3 results.

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

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