

A173423


Triangular numbers which are sums of 6 consecutive primes.


1



630, 990, 2926, 4950, 5886, 12720, 24090, 44850, 60726, 81810, 107416, 128778, 152076, 168490, 177906, 202566, 217470, 258840, 277140, 301476, 314028, 408156, 499500, 613278, 695610, 875826, 903840, 940506, 1205128, 1332528, 1405326
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OFFSET

1,1


LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..10000 (n = 1..528 from Robert Israel)


MAPLE

Primes:= select(isprime, [2, seq(i, i=3..10^7, 2)]):
P6:= Primes[1..6]+Primes[2..5]+Primes[3..4]+Primes[4..3]+Primes[5..2]+Primes[6..1]:
select(t > issqr(8*t+1), P6): # Robert Israel, Sep 26 2016


MATHEMATICA

f[n_]:=Prime[n]+Prime[n+1]+Prime[n+2]+Prime[n+3]+Prime[n+4]+Prime[n+5]; Select[Table[f[n], {n, 9!}], IntegerQ[Sqrt[1+8# ]]&]


PROG

(MAGMA) [ t: n in [1..22000]  IsSquare(8*t+1) where t is &+[NthPrime(n+s): s in [0..5]] ]; // Bruno Berselli, Apr 28 2011


CROSSREFS

Cf. A000040, A000217, A111163, A167788, A173420, A173421.
Sequence in context: A098261 A256937 A177421 * A295769 A110904 A171258
Adjacent sequences: A173420 A173421 A173422 * A173424 A173425 A173426


KEYWORD

nonn


AUTHOR

Vladimir Joseph Stephan Orlovsky, Feb 18 2010


STATUS

approved



