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%I #16 May 28 2020 05:31:20
%S 7839,8739,11248,12148,21148,44488,44489,44939,49439,70839,78039,
%T 80739,87039,94439,101248,102148,110248,112048,120148,121048,201148,
%U 210148,211048,222688,222689,226288,226289,236839,238639,258598,258599,262288,262289,263839
%N First of quadruples of consecutive happy numbers.
%H Amiram Eldar, <a href="/A194352/b194352.txt">Table of n, a(n) for n = 1..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/HappyNumber.html">Happy Number</a>.
%e 7839, 7840, 7841, 7842 are the first of four consecutive integers each of which is a happy number, hence a(1) = 7839.
%t f[n_] := Total[IntegerDigits[n]^2]; t = Select[Range[300000], NestWhile[f, #, UnsameQ, All] == 1 &]; t[[Select[Range[Length[t] - 3], t[[#]] == t[[# + 1]] - 1 == t[[# + 2]] - 2 == t[[# + 3]] - 3 &]]] (* _T. D. Noe_, Aug 22 2011 *)
%Y Cf. A007770, A035502, A055629, A072494.
%K nonn,base
%O 1,1
%A _Martin Renner_, Aug 22 2011
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