A154727 -id:A154727 - cp's OEIS frontend

A154785 Row sums of triangle in A154724.

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

Omar E. Pol, Jan 15 2009

Also, row sums of triangle in A154726.

Nathaniel Johnston, Table of n, a(n) for n = 1..10000

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

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

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

a(11)-a(50) from Nathaniel Johnston, Apr 19 2011

A154800 List of pairs of primes that are equidistant from and nearest to n, or the pair (0,0) if there is no such pair.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 3, 5, 3, 7, 5, 7, 3, 11, 5, 11, 7, 11, 7, 13, 5, 17, 11, 13, 7, 19, 11, 17, 13, 17, 13, 19, 11, 23, 17, 19, 7, 31, 17, 23, 19, 23, 13, 31, 17, 29, 19, 29, 19, 31, 23, 29, 23, 31, 19, 37, 17, 41, 29, 31, 19, 43, 23, 41, 29, 37, 31, 37, 29, 41, 31, 41, 31, 43, 29, 47

Offset: 1

Omar E. Pol, Jan 15 2009, Jan 18 2009

Conjecture: There are only six 0's in this sequence.

			Array begins:
n ............... Pair
1 .............. 0 . 0
2 .............. 0 . 0
3 .............. 0 . 0
4 .............. 3 . 5
5 ............ 3 . . . 7
6 .............. 5 . 7
7 ........ 3 . . . . . . . 11
8 .......... 5 . . . . . 11
9 ............ 7 . . . 11
10 ......... 7 . . . . . 13

Cf. A154720, A154721, A154722, A154723, A154724, A154725, A154726, A154727.

A154800 := proc(n) local d; for d from 1 to n-1 do if isprime(n-d) and isprime(n+d) then printf("%d,%d,",n-d,n+d); RETURN() ; fi; od: printf("0,0,") ; end: seq(A154800(n),n=1..80) ; # R. J. Mathar, Jul 13 2009

More terms from R. J. Mathar, Jul 13 2009

cp's OEIS Frontend

A154785 Row sums of triangle in A154724.

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