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A074924 Numbers n such that n^2 is a sum of two successive primes. 21
6, 10, 12, 24, 42, 48, 62, 72, 84, 90, 110, 120, 122, 174, 204, 208, 220, 232, 240, 264, 306, 326, 336, 372, 386, 408, 410, 444, 454, 456, 468, 470, 474, 522, 546, 550, 594, 600, 630, 640, 642, 686, 740, 750, 762, 766, 788, 802, 852, 876, 882, 920, 936, 970 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Zak Seidov, Table of n, a(n) for n = 1..22054 (all terms up to 10^6).

FORMULA

a(n) = sqrt(A062703(n)). - Zak Seidov, May 26 2013

EXAMPLE

6^2 = 17 + 19, 1610^2 = 1296041 + 1296059.

MATHEMATICA

Select[Sqrt[#]&/@(Total/@Partition[Prime[Range[50000]], 2, 1]), IntegerQ] (* Harvey P. Dale, Oct 04 2014 *)

PROG

(PARI) is(n)=if(n%2, return(0)); nextprime(n^2/2+1)+precprime(n^2/2)==n^2 \\ Charles R Greathouse IV, Apr 29 2015

CROSSREFS

Subsequence of A001043.

Numbers n such that prime(n) + prime(n+1) is a square are in A064397; n^3 as a sum of two successive primes in A074925; prime(n)+ prime(n+1) as a cube in A071220.

Sequence in context: A098669 A046363 A101086 * A064166 A107371 A213428

Adjacent sequences:  A074921 A074922 A074923 * A074925 A074926 A074927

KEYWORD

nonn

AUTHOR

Zak Seidov, Oct 02 2002

STATUS

approved

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Last modified April 29 11:38 EDT 2017. Contains 285604 sequences.